Weapons and items -
While playing a game, press ~ to display the console, then type "give [item]" 
using the following information. Other choices include "give all", "give 
weapons", or "give ammo".

ChainFist 
ETF Rifle 
Plasma Beam 
Prox Launcher 
Tesla 
Double Damage 
Hunter Sphere 
Defender Sphere 
Vengeance Sphere 
A-M Bomb 
IR Goggles 
Doppleganger 
Flechettes (ETF Rifle ammunition) 
Prox (Prox Launcher ammunition)

Level select -
Press ~ to display the console, then type "map [level code]" using the 
following information to skip to the corresponding level:

Name - Level code
Single player
Lower Mines - RMINE1 
Mine Engineering - RMINE2 
Thaelite Mines - RLAVA1 
Tectonic Stabilizer - RLAVA2 
Eastern Warehouse - RWARE1 
Waterfront Storage - RWARE2 
Logistics Complex - RBASE1 
Tactical Command - RBASE2 
Research Hangar - RHANGAR1 
Maintenance Hangars - RHANGAR2 
Waste Processing - RSEWER1 
Waste Disposal - RSEWER2 
Munitions Plant - RAMMO1 
Ammo Depot - RAMMO2 
Widow's Lair - RBOSS 

Multi-player
The Low Road - RDM1 
The High Road - RDM2 
Boxed In - RDM3 
Razor Close - RDM4 
Stone Hinge - RDM5 
Nexus - RDM6 
Sewer Citadel - RDM7 
Styx and Stones - RDM8 
Scenic Overlook - RDM9 
Great Divide - RDM10 
Dish It Out - RDM11 
Fall From Grace - RDM12 
Roads To Nowhere - RDM13 
Rogue's Edge - RDM14 

Other maps
Weapon and ammo depot - RUNIT2 
Weapon and ammo depot - RUNIT3 
Weapon and ammo depot - RUNIT4