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