Bring up the console by pushing the ~ key and type the following codes,
followed by the Enter key:
bind p positions - This will make the P key print out your position [x, y,z]. Ignore the decimal places.
a_moveme X,Y,Z - Moves you to the given position coordinates.
dir maps - List available maps.
map "mapname" - Start a map.
pc_spawnthing "thingname" Create an instance of an item or creature in the World. Try to be in an open area because you can spawn something inside a wall.
fly - Toggles fly mode on and off. Once on, press JUMP to fly. Then, quickly, turn it off to land.
ode to jack - Kill all creatures on level.
impulse 11 - God Mode.
bigfinale - Play the end sequence.
noclip - Turn clipping off (walk through walls).
impulse 10 - Large Magic attack
impulse 42 - Easter egg, displays "Technically, this is an easter egg."
impulse 43 - Instant death (1 of 5)
impulse 69 - Instant death (2 of 5)