Edit the "defaults.ini" file in the game folder. Change the "developer_mode = 0" entry to "developer_mode = 1". Save the file, then enter the "/configs" folder. Next, use a text editor to edit the "default.ini" file. Locate the cheat key section towards the end of the file and add the following entries:
[icPlayerPilot.DevIndestructable]
Keyboard, I, CTRL, ALT
[icPlayerPilot.DevKillCurrentTarget]
Keyboard, X, CTRL, ALT
[icPlayerPilot.DevJumpToCurrentTarget]
Keyboard, G, CTRL, ALT
[icPlayerPilot.DevDamageSelf]
Keyboard, K, CTRL, ALT
Start a new game, then press all three keys to activate the corresponding cheat function.