Yeah, I was thinking the wording was a little too vague. Because you can use the in-game cheats to quite literally fly through the game (vladicar + rifle + more powerful weapons cheat = hilarious results).

So, the rules states by any means possible. So, if I use the in-game cheats does that count? Because the game does not punish you for it like it does in, say, Goldeneye or Perfect Dark where using cheats prevents the level from counting as completed.

Secondly, despite living in the States, I am from the UK originally, and still have my original PAL version of Body Harvest. Well, on the PAL version, the difficulties are Hero and Zero. On Zero, you the game ends once you complete the American stage.

So, it's important to note the distinction between the NTSC and PAL versions for that reason.