Hints:

In the section where somebody is hurling grenades at you from behind the company sign, just destroy the sign. It will fall on him.

In the area where the Centipede Monster appears, keep it at bay by firing at its head until it arrives at the bridge. The bridge is supported by two wooden posts at each end; use CDs to knock down either the fore or aft posts and Centipede will fall along with the bridge.