Quake

CONTROLS:

To start Game, press Enter and Use ARROW Keys

Use ARROW Keys for movement
or
A (Left), W (Forward), S (Backward), D (Right)

Use MOUSE look and aim in any direction
Press CTRL Key  to use Weapon
Press ENTER to jump
Press SHIFT to run
Press ALT to sidestep
Press ??? to swim up and C to swim down

You can also customize the keys in the Controls menu!
(There is no Key set for swim up, so you may want to customize it)