Using the In-Game Console
While playing the game, press ~ (Tilde Key) to bring up the cheat console, and type $testcheats=1; to enable cheats.

From the console, you can use the following commands.

Command - Result
giveall(); - Replenish all weapons with 999 ammo
buy("ammo station"); - Ammo Station
exec(editor); - Enable Map Editor (For non-dedicated servers)
buy("energy pack"); - Energy Pack
setarmor(harmor); - Heavy Armor
buy("inventory station"); - Inventory Station
setarmor(larmor); - Light Armor
setarmor(marmor); - Medium Armor
buy("motion sensor"); - Motion Sensor
buy("turret"); - Turret

Alternative Method to Enable Map Editor
Type the following two commands, in order, to enable the map editor:

exec("scripts/editor.cs");
toggleEditor(1);