There are two bridges throughout the level packed with explosives which will activate as the player crosses over. Should one make their way to the other side, they will have a higher chance of obtaining a Spread Gun.
Bottomless pits; falling into one means death.
The base entrance is a big wall armed with two guns and an entry door. Be careful of the rifleman hiding up there. Destroy the two sentry guns outside the base before firing at the guns and the door.