If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Fortoresse is a multiplayer war browser game in 2D sidescrolling. Two teams fight in a war zone made of pixels. Each player can destroy the world or build a fortress made of pixels to protect himself and his teammates.
Arrow keys to move.
Space bar to build.
E to reload
Mouse click to shoot