There is a glitch. If you walk into a room and get attacked by a wizard but leave before the spell hits you (exit out the door you came in) you'll get stuck in the next room you enter.
Pay no attention to the brain till step three
1.Save for rocket launcher
2.Then get double damage
3.Save for chaingun
4.Unload on brain (and critters when necessary)
5.Use remaining money on rate of fire, 2nd damage tier, and whatever else you see if.
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