If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
The well known 3D ego shooter Doom comes now as a 2D action game!
A, D / Left, Right Arrow Keys - Move.
W / Up Arrow Key - Jump.
1-7 - Weapons
CTRL / Mouse - Shoot.
Spacebar - Open Door.
0 - Autoswitch Weapons.