It's quite simple, really. Two players — one red and one blue — out for blood. Attack your opponent with all of your might! A bomn (with an n!) does 5 damage, and "punching" your opponent (by running into them) does 1 damage.
Movement: Arrow keys
Drop bomn: Enter
Movement: W, A, S, D
Drop bomn: Spacebar
There are powerups scattered around the level that give you more bomns, fill up your health, and beef up your blast radius. There are also powerdowns that lower your blast radius, so be careful! The yellow stars are invulnerability powerups — collect one and you'll be impervious to harm for 10 seconds.
Those multicolored swirly doo-dads are warps. Step into one and hope for the best — you'll be transported to a random part of the level. If you're lucky, it won't be into the blast radius of a bomn!