Monday 17 October 2011

Gamebook Difficulty Index tested - Creature of Havoc/Invitation to a Feast

1 have tested my updated GDI (Gamebook difficulty index) system with a couple of gamebooks and have successfully calculated an (interim) GDI for each book.

The two books tested were:

- Creature of Havoc (A fighting fantasy gamebook); and
- Invitation to a Feast (My first gamebook).

I redid the score for Invitation to a Feast as the first score was calculated using the older (flawed) system.

As Creature of Havoc is a well-known gamebook in the Fighting Fantasy series (and is well-known as one of the toughest), I will give the final score calculated, including where the adventure ended each time I read the book, using the GDI system (spoilers ahead).

CREATURE OF HAVOC
1) Lost - Creature controlled
2) Lost - Fell off steps into the Bilgewater
3) Lost - Fell off bridge into the Bilgewater
4) Lost - Fell off steps and crashed into boulder by the Bilgewater
5) Lost - Pushed mine truck over a cliff and into the Bilgewater
6) & 7) Lost - Defeated by Darramouss
8) Lost - Captured in Yellowstone mines
9) Lost - Defeated by Chaos Warriors
10) Lost - Mud Slime
11) & 12) & 13) Lost - Couldn't open metal door (Final exit from dungeon)
14) Lost - Captured by Galleykeep (Tree noose trap)
15) Lost - Defeated by moving trees (Forest of Spiders)
16) Lost - Furnace Trap
17) Lost - Dree: Ambushed in alley
18) Lost - Sunk in muddy swamp
19) & 20) Lost - Captured by old woman in Dree
21) Lost - Pushed into muddy swamp by Toadman
22) Lost - Defeated by Hobgoblins (Galleykeep)
23) Lost - Enslaved by Red Cloak
24) Lost - Defeated by Quimmel Bone (Surgery)
25) & 26) Lost - Defeated by Zombie
27) Lost - Defeated by Hobgoblins (Galleykeep)
28) Lost - Joined Zharradan Marr
29) Victory

EXPLORATION SCORE = 29

1) Lost - Defeated by Dark Elf bowman
2) Lost - Defeated by Warrior & Thief
3) Lost - Defeated by Dark Elf bowmen
4) Victory

GAMEPLAY SCORE = 4

(INTERIM) GDI = 29 + 4 = 33

Recapping my explanation of the interim GDI and final GDI (from a previous post):

Finally, to wrap things up, I made a comment earlier that this score is what I classify as an interim score. The reason being is that I could just as easily test the book again and come up with a different score. What I plan to do is to indeed, test the book again, calculate the GDI and then calculate the average GDI based on the two tests. I will continue to do this until the average GDI varies by less than 1 point between tests. I will then conclude the test and consider the GDI as the final GDI. 

Looking at the breakup of this score, what it does show is that Creature of Havoc's famed high degree of difficulty lies almost solely with how well hidden the successful path is.  Once the correct path is found, Creature of Havoc is actually a very simple book to complete.

Comparing this to Invitation to a Feast, I came up with the following score: (warning - spoilers ahead)

INVITATION TO A FEAST
1) Lost - Deceived by otter
2) Lost - Invite snatched by Walter Weasel at Noble Items stall
3) Lost - Couldn't open Noble Ranger's gate
4) Lost - Invite snatched by Walter Weasel at Noble Items stall
5) Victory

EXPLORATION SCORE = 5

1) Lost - Invite snatched by Walter Weasel at Noble Items stall
2) Victory

GAMEPLAY SCORE = 2

(INTERIM) GDI = 5 + 2 = 7

I am currently calculating the GDI for my second gamebook, The Wounded Falcon.  At this stage, I am content with how the GDI system works and probably won't make any major changes to it now.

Wednesday 12 October 2011

GDI Rules Revisited

In my previous post, I mentioned (in an update at the bottom of the post) that frequent readings of the Fighting Fantasy gamebook, Creature of Havoc exposed a weakness in the GDI system.  I have since made some alterations to the GDI rules (including the addition of some rules I forgot to include in the previous post).

The new list of the GDI rules follow below:

THE EXPLORATION SCORE

RULE 1a): As a particular path to success is revealed and expanded upon while reading and re-reading the book, this partially revealed path to success MUST be followed in all subsequent reads.

This is the main change to the previous GDI rule system.  The previous rule 1 (now rule 1b) has been superceded by this one.

This rule is best explained by an example.  Let us say the correct path to success in a particular gamebook involved reading the following pages:

1 - 24 - 36 - 5 - 17 - 50

If, on the first read, you ended up reading pages 1, 24 and 36 and then went off the path to read pages 11 and 19, for all future reads you must always begin by reading pages 1, 24 and 36.  Continuing with the above example, on the second read, once you read page 36, the decision to turn to the correct page (5) or the incorrect page (11) will be decided by the remaining rules that follow below.

As a variation of the above condition, if it is possible to temporarily depart from the true path to explore other pages, without jepordising the following of the revealed path, this may be done, if the remaining rules (listed below) cause this to happen.  Using the above scenario again, if, on the second read, you read pages 1 and 24 and temporarily diverted from the true path (page 36) by turning to, say page 33, this is permitted if you eventually end up back at page 36 to continue along the correct path to victory without triggering an event that makes the book impossible to win.

Finally, if there are multiple paths to success (especially paths that are quite separate from each other), you can roll a die to decide which one to follow.

This rule overrides all other rules listed below.

RULE 1b): Each time the gamebook is read, it must be possible to complete the book EVERY time it is read.

This rule overrides all other rules listed below (but can be overruled by rule 1a above). The way it overrides the below rules is that it changes any potential compulsory selection of an incorrect choice to a random die roll between the correct and incorrect choice(s), where it is known that if the selection of a wrong choice is made, it will be impossible to successfully complete the book. (spoiler follows)

Example - In the Fighting Fantasy gamebook, "The Warlock of Firetop Mountain", one of the keys needed to open the chest at the end of the game is found early on, in a room, inside a box that contains a small snake. If any of the below rules force you to bypass the room that contains this key, you are to ignore the rule, but instead, roll a die to decide whether you enter the room or not.

RULE 2: When you are asked to make a choice between two or more pages to turn to, you must always turn to a page that you have not previously read.

Example. You walk along a road and arrive at a junction where you can travel to the east or west. If you travel to the west on your first read, you MUST travel to the east on your second read.

The above rule has two critical exceptions: Rule 1 (both parts - see above), and the below exception.

RULE 2 (exception): If, on a previous read, you have discovered that possessing an item of equipment or event (codeword) is needed to turn to a previously unread page, and you know both:


a) How to get to the page where you gather the item of equipment or codeword; AND
b) You have previously read the page where you cannot proceed to the unread page without having the item or codeword,


You MUST select the page number that will get you first to the item of equipment or codeword.

This is a complex exception and is best illustrated by using an example (spoiler follows):

In the Fighting Fantasy gamebook, Citadel of Chaos, the villain, Balthus Dire, has a combination lock to get into his war room for the confrontation at the end of the game. Let us say, for example, when reading the book, you discover the combination lock for the first time, but do not have the number for the combination.

Continuing on, in a later read, let us assume you discover the location where the combination is found but do not get to the combination lock at the end.
Because you have discovered both parts of the "solution" to this particular puzzle, for ALL subsequent reads of the book, you must ALWAYS seek out the combination first so that it can be used to unlock the room at the end, because there is an unread page that needs to be read. As long as there are still unread pages to be read after unlocking the door to the war room, this general path (seek the combination first) must be followed on every subsequent read.

If you have multiple examples of the above event, (i.e. You have discovered more than one item/codeword and where it can be used later on in the story), you must roll a die to decide which item/codeword you focus on (unless, of course it is possible for you to follow both).

RULE 3: When you are asked to make a choice between two or more pages to turn to and there are more than one unread pages to choose from, you must roll a die to choose between them.

This rule was alluded to earlier. Again, it encourages exploration of the entire book. Rule 1 (both parts) and Rule 2 (exception) can override this rule, however.

RULE 4: When you are asked to make a choice between two or more pages AND all of these pages have been previously read:

a) Select a page that will eventually lead you to an unexplored area
b) If all pages (or none) eventually lead you to an unexplored area, then roll a die to choose the next page

Where possible, all of the above rules can override this rule.

RULE 5: Making choices that do not involve turning to a page.

A typical example of this is choosing a list of items to buy from a store, merchant etc. where all the items are listed on the one page. In this scenario, once again, you roll a die to choose whether to buy an item or not. If you have limited money, then once again, you roll a die to reduce your selection of items to buy. Again, this rule can be overriden, primarily by rule 1 (both parts) or the rule 2 exception.

RULE 6: Avoid the instant failure page

If you reveal a path that leads to certain failure, you are not to follow that path again, if at all possible.

THE GAMEPLAY SCORE

Thankfully, the calculation of this score is very simple. All you have to do is the following:

1) Read the gamebook again as you would normally read the gamebook (i.e. All gamebook mechanics are reinstated).

2) Using the path to victory you discovered when calculating the exploration score, as much as is possible, read the story through to its conclusion.

Expanding upon the phrase in point 2), "as much as is possible", here is a scenario where you may deviate from the pre-determined path to victory.

Example - Let us say, when calculating the exploration score, you followed a path that involved a section when you had to battle a difficult enemy that could have been avoided.  If, when reading the book with all gamebook mechanics reinstated, you were defeated by this enemy, you need to consider factors such as (using a Fighting Fantasy themed example):

What was your skill at the beginning of the story?
What was your stamina at the beginning of the story?

This can be up to the reader to determine, but if you had a starting skill of 9, but lost to the difficult enemy, the next time you read the book, and roll a starting skill of, say, 8, this may be a scenario where you choose to deviate from the pre-determined path and find a better one.  The process of finding an easier path would be up to the reader to decide.  There is no need to follow complex exploration rules like before because we have already calculated the exploration score at this point.  Continuing on, if you roll a starting skill of 10, because your chances for success are slightly better than before, you would remain on the same path and battle the difficult enemy.  If you lost again, perhaps you would not try that path again unless your starting skill was greater than 10, and so on and so forth.

This is just a small example of how to apply the intent of the principle that lies in the phrase "as much as is possible", in point 2.

So, there are the updated rules.  I hope the adjustments make the GDI a strong measuring device for the difficulty level of any gamebook.

Jasan

P.S.  Now that the system has changed, I'm going to go back and re-calculate the score for "Invitation to a Feast", amongst other things....

UPDATE

I made a small adjustment, reinstating what is now rule 1b.  Previously, I removed it altogether, and then realised that it still served an important (though reduced) purpose.

Friday 7 October 2011

The GDI (Gamebook Difficulty Index)

One of the most intriging parts of a gamebook is that you are attempting to achieve a goal by successfully completing the story.  Some stories have multiple successful endings, some have just the one.  In each of these stories, though, depending on the author, the difficulty level involved in attempting to complete the adventure varies from book-to-book.

For the past many weeks I have been attempting to construct a system that can be used to measure the difficulty of any gamebook written by giving it a difficulty rating.  Hopefully it can be something that people can use to rate different gamebooks when wanting to choose one to read.  I expect it will also be something people enjoy using to settle debates on which gamebooks are tougher (or easier) to complete.

I don't expect this system to be perfect, though I have tried to make it as unbiased and fair as I could think of.  I welcome any feedback on the system and any potential improvements people might think of.

I have called the system the GDI (Gamebook Difficulty Index).  The main principle I followed when constructing the GDI was that the skill of the reader was taken away when determining the final score (or index).  In the years of reading gamebooks, I have noticed that some readers have had a knack of finding the successful ending(s) more quickly than others, and I wanted that element to be totally removed.

The rules in determining the final index are basic in general terms but are also quite detailed in others.  I will explain how the index works in its most basic terms and then elaborate on some of the complexities (but not all at this stage - I will probably do this in later blog entries or this particular blog post will be too large).

I have applied the index, at this stage, to only one gamebook - My first gamebook, "Invitation to a Feast", a book that I have always considered to be a reasonably easy gamebook to complete.  At this end of this post, I will state what GDI I gave my gamebook, and then explain why the rating is not a final rating but is an interim rating.

Anyway, enough intro....let's begin!!!

The GDI consists of two components:

a) An exploration score; and
b) A gameplay score.

The GDI equals the exploration score plus the gameplay score.

THE EXPLORATION SCORE
In plain English, the exploration score represents the amount of times one has to read the book to find the successful ending in the gamebook.  If there is more than one successful ending to find, the score represents the amount of times one has to read the book to find any of the successful endings in the book.

At first glance, this score appears to cover all bases, but this is not the case.  When determining the exploration score, all gameplay mechanics are excluded from the book, which generally means all the die rolling mechanics are removed from play when reading it.

Using Fighting Fantasy gamebooks as an example, this means that:
- All combat is removed (you assume that you always win)
- All other die rolling is removed (E.g. Test Your Luck, Skill, Stamina etc.)

For the purposes of working out the exploration score, the story is (almost) reduced to a straightforward Choose Your Own Adventure story.  What is retained, however, is:
- Collecting and using equipment
- The use of Codewords or Events
- Other such similar devices (i.e. Non die-rolling mechanics)

So, just repeating, the score itself is the number of times one reads the book until a successful ending is found.  If you remember my earlier comment, however, my intention is that the skill of the reader is taken out of consideration.  The way this is dealt with is by:

RANDOM NUMBER SELECTION.

In other words, if you read a page of a gamebook and are presented with three choices to select from at the end of the page, rather than make the choice yourself, you allow the roll of a die to determine what choice is selected.  This general principle is followed all the way through the book until a successful (or unsuccessful) ending is found.  If your adventure ends, you go back to the beginning of the story and start over.

BUT WAIT!  BY USING THIS METHOD, IN ALL LIKELIHOOD, IT COULD TAKE HUNDREDS OF READS TO FIND A SUCCESSFUL ENDING (ESPECIALLY IF THERE IS ONLY ONE OF THEM TO FIND.)

The above statement is quite valid.  To prevent this from happening, however, there are a number of specific rules to follow when reading, so the exploration score that is calculated is a reasonable and realistic one.  These rules are where the complexity of determining the GDI is at its highest.

The rules/principles are as follows:

RULE 1: Each time the gamebook is read, it must be possible to complete the book EVERY time it is read.

This overriding principle is to prevent the reader from wasting many reads wandering along incorrect paths, where there is no chance of final success.  This principle also makes it obvious that when determining the GDI of a gamebook, one must first already know the true path or paths that must be taken to succeed. 

Originally, when designing the GDI, I wanted to give the reader the opportunity to calculate the GDI for a book that he/she had never read before.  This, for me, resulted in many problems (mainly revolving around wandering along incorrect paths for many reads on end and inflating the GDI to what amounted to ridiculous levels).

This rule overrides all other rules listed below.  The way it overrides the below rules is that it changes any potential compulsory selection of an incorrect choice to a random die roll between the correct and incorrect choice(s), where it is known that if the selection of a wrong choice is made, it will be impossible to successfully complete the book.  (spoiler follows)

Example - In the Fighting Fantasy gamebook, "The Warlock of Firetop Mountain", one of the keys needed to open the chest at the end of the game is found early on, in a room, inside a box that contains a small snake.  If any of the below rules force you to bypass the room that contains this key, you are to ignore the rule, but instead, roll a die to decide whether you enter the room or not.

RULE 2: When you are asked to make a choice between two or more pages to turn to, you must always turn to a page that you have not previously read.

Example.  You walk along a road and arrive at a junction where you can travel to the east or west.  If you travel to the west on your first read, you MUST travel to the east on your second read.

This rule is to encourage exploration of all possible page numbers in the book, thus logically ending in the eventual discovery of the page number where you successfully complete the book.

I use an excel spreadsheet to create a gamebook flowchart to track which pages I read on each occasion and highlight the page numbers that have already been read.

The above rule has one critical exception, however (not including rule 1 above, of course).

RULE 2 (exception): If, on a previous read, you have discovered that possessing an item of equipment or event (codeword) is needed to turn to a previously unread page, and you know both:

a) How to get to the page where you gather the item of equipment or codeword; AND
b) You have previously read the page where you cannot proceed to the unread page without having the item or codeword,

You MUST select the page number that will get you first to the item of equipment or codeword.

This is a complex exception and is best illustrated by using an example (spoiler follows):

In the Fighting Fantasy gamebook, Citadel of Chaos, the villain, Balthus Dire, has a combination lock to get into his war room for the confrontation at the end of the game.  Let us say, for example, when reading the book, you discover the location where the combination is found but do not get to the combination lock at the end.

Continuing on, in a later read, let us assume you discover the combination lock for the first time, but this time, do not have the combination.

Because you have discovered both parts of the "solution" to this particular puzzle, for ALL subsequent reads of the book, you must ALWAYS seek out the combination first so that it can be used to unlock the room at the end, because there is an unread page that needs to be read.  As long as there are still unread pages to be read after unlocking the door to the war room, this general path (seek the combination first) must be followed on every subsequent read.

If you have multiple examples of the above event, (i.e. You have discovered more than one item/codeword and where it can be used later on in the story), you must roll a die to decide which item/codeword you focus on (unless, of course it is possible for you to follow both).

RULE 3: When you are asked to make a choice between two or more pages to turn to and there are more than one unread pages to choose from, you must roll a die to choose between them.

This rule was alluded to earlier.  Again, it encourages exploration of the entire book.  Rule 1 and Rule 2 (exception) can override this rule, however.

RULE 4: When you are asked to make a choice between two or more pages AND all of these pages have been previously read:

a) Select a page that will eventually lead you to an unexplored area
b) If all pages (or none) eventually lead you to an unexplored area, then roll a die to choose the next page

Where possible, all of the above rules can override this rule.

RULE 5: Making choices that do not involve turning to a page.

A typical example of this is choosing a list of items to buy from a store, merchant etc. where all the items are listed on the one page.  In this scenario, once again, you roll a die to choose whether to buy an item or not.  If you have limited money, then once again, you roll a die to reduce your selection of items to buy.  Again, this rule can be overriden, primarily by rule 1 or the rule 2 exception.

I realise this is a complex system, and I would not be surprised if some of you that read this end up totally confused by it.  For those of you who can follow it, I welcome any feedback on it.  This system certainly does not have to be the final system and if somebody can find a way to genuinely improve it, I welcome any suggestions.

So, in summary, after following the above rules, you will eventually find a successful ending to the gamebook.  Once this is done, apart from recording how many times the story had to be read in order to win, you must move along to the next element of the GDI....

THE GAMEPLAY SCORE
Thankfully, the calculation of this score is very simple.  All you have to do is the following:

1) Read the gamebook again as you would normally read the gamebook (i.e.  All gamebook mechanics are reinstated).
2) Using the path to victory you discovered when calculating the exploration score, as much as is possible, read the story through to its conclusion.

Similarly, the gameplay score is the number of times one reads the book until the same successful ending, discovered while determining the exploration score, is found.

That's it!  The total GDI, I think, is a reasonable score that should represent the average number of times you would expect an average gamebook player to read the book through to a successful completion.

INVITATION TO A FEAST
As I mentioned earlier, I have used this system to rate my first gamebook, "Invitation to a Feast", and this is the score I came up with:

EXPLORATION SCORE = 3
GAMEPLAY SCORE = 1

GDI = 4

Finally, to wrap things up, I made a comment earlier that this score is what I classify as an interim score.  The reason being is that I could just as easily test the book again and come up with a different score.  What I plan to do is to indeed, test the book again, calculate the GDI and then calculate the average GDI based on the two tests.  I will continue to do this until the average GDI varies by less than 1 point between tests.  I will then conclude the test and consider the GDI as the final GDI.

A fair bit involved, yes, but I think, a worthwhile exercise, particularly for those who enjoy statistics (like I do!).  What I am most pleased with is that this system is unbaised and impartial and will really come into its own, once some final GDIs for different gamebooks are calculated.  We should then be able to compare gamebooks and truly classify them from easiest to complete to hardest to complete.

The next book I plan on rating is one of the most famous and difficult Fighting Fantasy gamebooks written, Creature of Havoc.  I am certain the GDI will not be a low as 4 for this one!

Thanks for reading,

Jasan

========================

UPDATE!!!

Thanks to all those who made comments about this system on this site (and other sites that I frequent).  I plan on responding when I get a chance but the feedback, so far, has been appreciated.

In the ensuing analysis by myself and others since I released this article, some weaknesses in the system have come to light.  In particular, I gave the system a real workout by testing it with the fighting fantasy gamebook, "Creature of Havoc".  I figured that if any gamebook would find any faults with my system, Creature of Havoc would deliver the goods, and it did.

For those of you who are familiar with the story, my system broke down when it became apparent that it was very, very difficult to find the vapour of tongues (language) when using my original system, and did not represent a realistic scenario at all.

I have since made an appropriate adjustment to rule 1 (which was the main cause of the problem).

I also realised that I forgot to include a couple of rules in my original post.

Rather than edit the original entry (above), I will make a new blog entry with the updated system, so those of you who are interested can follow the natural evolution of the GDI from its beginnings, to where it is now.

With the adjustments made, I have found that I can now progress through Creature of Havoc in a gradual, realistic way each time it is read.  I haven't yet completed the story but I don't envisage any great problems with the GDI now.  Any further changes from now on, should be minor (if any, I hope!)

Jasan

P.S.  The updated GDI system will follow in a new post once I have written it.  If I get a chance, I may explain in more depth how the original system failed, for those of you who are interested.