If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Help Zack to find what's going on in the biomedicine lab where he works. Move with the arrow keys. Press Q to open your inventory. Press the space bar to open the doors. Use the mouse to choose objects from the inventory. Make click to attack. Press R to reload your weapon. Press the Caps lock to turn the light on.
Q - To choose weapon.
R - to reload.
W,A,S,D/Arrow keys - To move/jump.
Mouse key - To aim and shoot.
Space bar - To open doors/climb out.