It is very blatantly inspired by Phutball, which I was playing at the time on Richard Rognlie's Play-By-Email Game Server, which, to my utter astonishment, appears to still exist 17 years later.
The idea is you click on the little circles to add tokens to them, and click on the arrows to spend the tokens moving the "ball" that is initially in the center of the field. You can only spend tokens in the row or column the ball is currently in. The twist is that when a player decides to "kick" the "ball" by spending the n tokens from my row, n tokens (if available) are also deducted from the opponent's row. This seems to incentivize strategies away from head-on competition within one row.
Still not totally sure if it's very interesting tactically or whatever, but it was fun to code up.