Owkej so far i find level8 the thoughest one did 3days over it.
But now i'm on lvl10 and since i don't see any thread about it, i'm gone ask it over here what am i searching for? I just see hints in the source and evrything but getting nowhere.
I think that 76 may have been the hardest, 79 was easy to figure out the correct path. I spent overall the longest time on minus 6 because I couldn't for the life of me figure out the specification needed.
So far -14 is definitely the hardest (though 80 took me forever!) . It's all the more annoying because it seems everyone else found it so easy and I can't even begin!
Forget all previous levels mentioned in this thread. The hardest level to pass by far is Minus 31. Made 72 and 76 look like a breeze. at least to me anyway.
level 72 and level 81...
the first one was simply difficult to think about...
and the second one made me feel stupid after I solved it (two days...and the answer was under my nose...)