WASD move
Mouse look
Shift sprint
Space jump (onto the fire step) hold
Space at a wall to climb out
C crouch / stand up
W into a ladder: climb
Esc pause
E take your weapon
Left click fire
Right click aim (rifle)
R reload
12 swap weapons
T knife
G grenade (at a tank's gun: down the barrel!)
Player 2 (right half): a game controller — left stick move, right stick look, RT fire, LT aim, A jump / take, B crouch, X reload, Y swap, RB grenade, LB knife, click the left stick to sprint
or the keyboard: ↑↓ walk, ←→ turn, Num 8Num 2 look up / down, Num 4Num 6 sidestep, Num 0 fire, Num . aim, Num Enter jump / take, Num 5 crouch, Num + reload, Num − grenade, Num * knife, Num / swap / pick, Right Shift sprint