I finished the game, finaly
maybe spoilers for some
only cheated twice
first it was the level where you are dumped at a hilltop with one rifle and sfsckngin 10 bullets, could have probably sneaked past all the critters but it would have just taken too many tries, ended when I was at the river, or sea, the water that parted the level
second was the last level, I mean I was only playing it at easy but that map is impossible!! it takes 8-10 shotgun shells to kill one of those bastard and I even used the rockets on one, all direct hits and needed 5 rockets to take one down!!