Portal/Controls

Movement

 * : Look around.
 * W, A, S, D: Move forward, left, backward or right, respectively.
 * Space: Jump.
 * Ctrl: Crouch.

Combat

 * : Fire red portal.
 * : Fire blue portal.
 * E: Pick up object or use items (e.g. buttons).

Miscellaneous

 * F5: Take screenshot.
 * F6: Quick save.
 * F9: Quick load.
 * Pause: Pause game.
 * `: Toggle console.