Show HN: Pressure – a simple 2D board game in JavaScript
ilmenit.github.io
Pressure is played on a 5×5 grid with 12 tokens total. The key mechanic is a "push" feature where tokens can displace entire lines of other tokens if there's an empty space at the end of the line. When opponent tokens are pushed, they become inactive for one turn. Capture occurs when tokens are surrounded on all four sides.
After analyzing gameplay data, I found Pressure has an average branching factor of 11.5, which is higher than Othello (10) and Checkers (2.8), though lower than Chess (35). Its game tree complexity is approximately 10^57, placing it remarkably close to Othello (10^58) and much higher than Checkers (10^40), despite the smaller board size.
The state space complexity appears to be in the range of 10^20, comparable to Checkers, which is notable given Pressure uses a 5×5 grid versus Checkers' 8×8 board. Chess and Othello have higher state spaces at 10^44 and 10^28 respectively.
What's computationally interesting is how the push mechanic generates this complexity. About 27.5% of all moves involve pushing, which creates a multiplicative effect on the decision space. Each push can reposition multiple tokens simultaneously and create cascading positional consequences beyond what the compact board size would suggest. I've found the average game length is approximately 50 moves, similar to Othello (58) but shorter than Chess (70) and Checkers (70).
Let me know what do you think about the game.