By entering these cheats on the screen when you're playing, you get the effect.

Display frame rate: frametime
Chase view perspective: longchimp
Toggle random pattern textures; scrambles automap and main menu :weirdtexture
Weaker ship :gabbagabbahey
Weaker ship :zingermans
Weaker ship :motherlode
Weaker ship :alifalafel
Weaker ship :delshiftb
Weaker ship :fopkjewa
Weaker ship :eatangelos
Weaker ship :gowingnut
Weaker ship :freespace
Weaker ship :ahwlmbpf
Weaker ship :honestbob
Weaker ship :farmerjoe