Make use of Sniper mode as Kurt. An enemy taken out
from afar is an enemy you don't have to worry about
later.

If concerned about ammo as Max, switch to the main
pistol it won't run out. Save the Uzis for rougher 
times.

Dr. Hawkins requires an unorthodox approach. Save 
often and try everything; you'll stumble upon the 
answer eventually.

When facing the first boss as Kurt, zoom in and look
for those blue globes. There are four in the middle
and two orbiting the ship.