Below are a list of cheats which can be entered into the game's developer console:
To turn on the developer console, go to Options, Keyboard Tab, Advanced Buttons and check the Enable Developer's Console selection. Save your changes and when you are next in gameplay, or in the main menu, use the ~ (tilda/SHIFT+hash) key to access the console.
To enable cheat mode, enter: sv_cheats 1
You can now use any of the following commands:
Bullet Time Macro: host_timescale - Changes the game speed. 1 is regular, 2 is fast, 0.5/0.75 is slow.
Turn off Cheat Mode: sv_cheats 0
Infinite Run/PsiForce: sv_infinite_aux_power 1
Normal Run/PsiForce: sv_infinite_aux_power 0
Refill Ammo: givecurrentammo
First Person View: firstperson
Third Person View: thirdperson
Third Person View with alternate control scheme: thirdperson_platformer 1
Note that you can save cheats, and the initial sv_cheats 1 command itself to save time in the future using the Bind tool. Type bind, followed by a command, followed by the cheat, to bind that key to the cheat I.e. Type 'bind c sv_cheats 1', you will activate cheats at the push of the 'c' key.