The controls are simple, but mastering them takes time, especially with the high speed of the gameplay. Use Arrow Keys or WASD to move and jump. Shooting: Use Z or J to shoot your main weapon.
Because Broforce is a commercial standalone game, full browser-based "unblocked" versions are usually fan-made ports, demo versions (like the famous Brotforce or Expendabros promotional spin-offs), or hosted via custom emulators.