Knife Edge on N64 I couldn't even beat the final level, ever. I would always die when you fight the alien with the claws that injests your commander. Another frustrating one was Winback: Covert Ops on PS2 on Hard difficulty. Limited health packs, awful checkpoints and those f-annoying instant death red lasers! It took me over a month to complete it. An honorable mention is Day of The Tentacle on Mac which is virtually impossible to figure out without looking up on what to do next via the Internet.