Press ~ to display the console, then type one of the following codes to activate the corresponding weapon.

give ionripper
give phalanx,
give trap
give mag slug
give dualfire damage
Level select:
Press ~ to display the console, then type map using the following information.

Name - Level code
The Swamps - xswamp
Sewers - xsewer1
Waste Sieve - xsewer2
Outer Compound - xcompnd1
Inner Compound - xcompnd2
Core Reactor - xreactor
The Warehouse - xware
Intelligence center - xintell
Industrial Facility - industry
Outer Base - outbase
Water Treatment Plant - w_treat
Badlands - badlands
Refinery - refinery
Lower Hangars - xhangar1
The Hangars - xhangar2
Strogg Freighter - xship
Cargo Bay - xmoon1