The Horror

While waiting for Apple to approve the iPhone/iPod touch port of my Wii hombrew game Horror Vacui I thought I would jot down some notes on the evolution of the game mechanics. (Keep in mind that these are notes on the process and are not intended as an explanation of how to play the game. Many of the terms and rules continued to evolve after this initial exercise.)


The idea for this game started as incoherent, late-night scribbles about water and earth and their opposing natures at different temperatures; somewhat inspired by the element spell/enemy pairs in Final Fantasy games. I had a vague notion that it should be a two player abstract strategy board game (conceptually, if not physically).

As good a place as any to start but the idea was still very abstract. Games need goals and rules. So I decided players should take turns (obvious) placing pieces representing their element on a 4x4 grid (arbitrary) that when filled the player with the most pieces on the board wins (traditional).

Goals are easy. When combined with the initial concept, the goal suggested a name for the game, Horror Vacui, from the antiquated theory that “Nature abhors a vacuum.” So the board became known as The Vacuum. The rules of how the two players’ pieces interact took a bit longer to suss out.

Opposites Detract

For a while I toyed with ideas about the different physical states of the element (in addition different temperatures). Both have vapor, liquid and solid states. Water with mist, water and ice. Earth with dust, lava and earth. But this extra level of detail only confused how the two elements should interact (eg. water’s liquid state is at normal temperature while lava is molten earth—never mind having to map dust to cold).

After eliminating that tangent I decided that on each player’s turn they would select a card from a deck that would randomly determine whether their next piece played would be normal temperature, hot or cold. When placed, its temperature would affect any adjacent pieces—of both players. Matching extremes would eliminate the adjacent piece and opposing would normalize the temperature of adjacent pieces.

I also created two wild cards labeled “Cold Wind” and “Heat Wave.” These would move across the board in a predefined pattern (a straight line for Cold Wind, a sawtooth wave for Heat Wave) with a location determined by the player (who would not set a piece for that turn).

Rules are made to be broken

With the rules ironed out I started to build a prototype with jQuery but quickly decided against going straight into code. I remembered reading about paper prototyping for games (probably on Danc’s Lost Garden or SCAD professor’s Brenda Brathwaite’s blog) so I gave that a go (despite the hand cramp it was fun not staring at a screen for the hour it took to color and cut the pieces). Only to find that the rules (and goal) I laid out didn’t work so well.

For one, draws were extremely frequent since it was a two player game on a board with an even number of cells with occupant majority determining which player wins. Apparently goals aren’t so easy after all. Also, it was too easy for the two players to cancel out each other’s previous move without moving the game forward. This resulted in many interminable games. Finally, explaining the Heat Wave wild card to a second player (as opposed to a computer which would just draw a preview of the moves effect) proved difficult.

The Draw problem could have been solved two ways. I could increase the size of the board giving it an odd number of cells or institute a fallback rule that gives the win to the player with the most normal temperature pieces (which are more stable in terms of gameplay). The second option didn’t eliminate the problem but suggests and encourages a good way to approach the game. In order to play effectively it’s best to balance “attacking” your opponent’s pieces with normalizing the temperature of your own—making them less susceptible to “attack.” I’m actually glad I made a mistake in arbitrarily choosing a grid size—it gave me useful insight into how the game actually works.

The Wild Card problem was the easiest to resolve. Wild cards should affect all of the pieces on the board. They were renamed to “Ice Age” and “Fire Storm” to reflect their new all-encompassing nature. Matching extremes are eliminated, normal temperatures switch to the extreme and opposing extremes revert to normal temperature. The results can be absolutely devastating to one or both players and creates an incentive to normalize your pieces.

Are we there yet?

Resolving the Interminable Game problem proved to be a bit harder. Because temperature is determined randomly there is always a chance that plugging the last hole in the board will open the board back up—sometimes requiring a player to eliminate one or more of their own pieces. I considered limiting the number of pieces played but that conflicts with the goal and the concept of the game.

Over the course of a couple of hours play-testing the paper prototype I refined some of the interaction rules and added some new ones to minimize the occurrence of interminable games. First, when an extreme has an impact on an adjacent piece, the incoming piece is restored to normal temperature. This provides positive feedback for playing offensively or defensively depending on the situation. It also reduces the number of “fragile” extreme pieces on the board at any given time making it less likely for a newly added piece to be picked off on the next turn since a normal piece requires two “attacks” before it is eliminated while an extreme piece needs only one.

A new Sacrifice Rule was added that allows a player to sacrifice a freshly drawn extreme element to normalize an opposing extreme piece already on the board. This allows players to avoid weakening their own pieces or strengthening an opponents piece simply to play a given piece. It also adds another level of strategy when combined with the final revision to the goal.

The new goal (on a 5x5 board) is to fill the board with the most normalized pieces. In the event of a tie the player with the most pieces on the board overall wins.


With those revisions made I had a playable and more importantly enjoyable game design. The entire concept and prototyping process took about two days. The next day was spent designing the old school 8-bit graphics. By the end of the following day I had a playable Wii version of my paper prototype. It lacked music and sound effects, animation, title/game over screens and a CPU opponent but with two Wiimotes in hand I could watch the game unfold onscreen in real-time based on the rules and goals I had established.

See also, Eye of the Abhorrer, notes on the visual and audio design of Horror Vacui. Thank you for reading but our princess is in another article!

Coming Soon
Game Design Workshop
Shaun Inman
February 3rd, 2009 at 11:04 am