I'm having A LOT of trouble with the Icarus Potion Challenge. A LOT.

Is there any way to go into the save data and make the game think that i have completed the challenge?

yes, but it isn't trivial. i've unlocked a couple of things by hand, and it's a bit of a pain. didn't somebody write a program that effectively does that? if not, somebody should.

I think there's a 100% save somewhere, but it's french, and not exactly what you want.

there are multiple 100% save games in english and in other languages, although ya should do like I did and just beat it (I found the super sheep challenge to be the hardest actually..). As per an unlocker tool, no idea.. think most of em just do it thru save game file.. I will note if you use that method, you'll write over your team and any accomplishments you've done yourself :s