It's meant to be challenging, something that a lot of more recent games lack. It incorporates puzzles with shooting brilliantly and with some mucking about in the console it lets you ricochet an unending supply of crossbow bolts into the faces of zombies and spawn near infinite numbers of airboats on their corpses! That kept me amused for so long.
Seriously guys: open console, turn cheats on, bind impulses 83 and 101 to hotkeys, turn on godmode and let the crazy fun times commence!
To add to the challenge, on hard difficulty a gunship takes more rockets to down than you can carry. Good luck getting back to the supply crate.