Dev Blog - AquaBlock - Puzzle Difficulty (and designer rules)

This post covers how difficulty can be approached in puzzle design and why it is harder to create an easily solvable puzzle than a difficult-to-solve puzzle.

Everything you see in this post is work in progress.

Defining Puzzle Difficulty

Here are factors that I found helped define a puzzle’s difficulty.

1. Number of Puzzle Pieces
   The quantity of pieces in a puzzle controls the time required in solving a puzzle. Each additional piece increases the number of possible outcomes the player has to consider. The ideal for this factor is try and get the piece count as low as possible while letting the puzzle serve it’s purpose. Every piece costs the player time, so don’t waste it.

2. Number of Puzzle Mechanics
   The amount of unique puzzle mechanics the player has to consider sets a skill/knowledge gate. This number should be reasonably low to avoid having the player be overloaded with the amount of knowledge they have to recall.

3. Preceding Information
   As a broader factor, any relevant puzzle information that surrounds the puzzle helps to smooth out the difficulty curve. Information that is not specifically a part of the puzzle can still be valuable to the player, like puzzle titles, themes, or even music.

Establishing Rules

Designer Rules

With the list of difficulty factors in mind, I established a few rules for myself for designing the puzzles in AquaBlock.

1. Piece Selection Limit
   The self-enforced limit for pieces in a puzzle is currently six. There’s no hard formula that was used to calculate this, it was decided through testing. Six appears to be the magical number where the piece count just starts reaching the point of being overwhelming.

2. Piece Size Range
   Each piece in AquaBlock can potentially be made up of nine blocks. A larger piece means there are less potential places to drop it, making it easier to drop.

3. Block Type Limit
   The limit for different block types allowed in a single puzzle is three. This limit also does not have a hard formula attached to it; it mostly comes from the small scopes of the puzzles and the limited puzzle types currently.

Player Rules

Along with the behind-the-scenes rules that apply to me for designing, there are also some forward-facing rules that the player perceives.

1. 3x3 Cube
   The player can only encounter a 3x3 cube puzzle; there are no other dimensions that the player has to consider. This hard limit keeps the scope of the manageable and conditions the player to approach each puzzle in similar ways.

2. All Pieces Required
   The player always has to use all the pieces provided; there are no extra pieces and the pieces are never out of order. This simple rule gets the player to analyze all puzzle pieces at the start of a puzzle.

Design

Why establish rules for myself?

The "Player rules" are an attempt to playpen specific player behaviors and hopefully make the game easier to understand; the purpose of the designer rules is similar. The "Designer rules" help translate Game Design abstractions into rigid guidelines. So instead of constantly trying to figure out why I'm implementing things in a certain way, I can trust the rules I set in place at the start of production to guide my design.

What are some mistakes made?

While trying to have a larger puzzle piece count on some puzzles, I realized that I was creating “No-Choice blocks”, or puzzle pieces that didn’t offer any options in terms of possible placements. These blocks were acting as “puzzle filling", so I tried to avoid creating too many of these.