Eternal Darkness for Gamecube: this big guy coming from the floor was impossible.
Tomb Raider Angel of Darkness for PS2: can't get around these lasers in this hallway.
Shenmue II for Xbox: Xbox died on me.
TMNT for NES: never owned the game. Have Rom, but feel awkward playing with keyboard.
Punch-Out for NES: Mr. Dream is Uber difficult.
Legend of Zelda: Link to the past for SNES: too much like ocrina of time to bother with.
Legend of Zelda for NES: freakin catridge memory kept getting lost.
Abes' Oddysee for PSX: couldn't find a dude to rescue.
Quake II expansions for PC: the game wasn't good enough to endure the bugs.
Star Craft for PC: Eh, didn't feel like playing with other races.
Final Fantasy 8 for PSX: As if I was gonna search the entire ocean for a stupid ship.
Final Fantasy III for SNES: never owned it, but borrowed it and it was great.
Batman for NES: not even with game genie, could I beat Joker.
Batman Forever for Gamegear: couldn't get past the circus.
Sonic the Hedgehog for Gamgear: couldn't get past this level with really far jump.
Surf Ninjas for Gamegear: don't remember beating it.
Sonic the Hedgehog 3 for Sega Genesis: Stupid casino.
Mario: Lost levels for SNES or gameboy: all I remember is a really high wall.
Back to the future for NES: I did beat it with the help of saving from an emulator, but would never be able to beat it otherwise. The ending sucks ass. It's akin to "THE END."
Rainbow Six for PC: I don't remember.
Stupid Invaders for Dreamcast: HARD.
Dracula Unleashed for PC/Mac/Sega CD: used walkthrough, too hard, waste of time to just guess your way to the ending.
Sonic CD for Sega CD: Don't remember beating it, but it is one of the coolest sonic games evar.
Private Detective for 3DO: It was confusing. didn't understand last level. But cool game though.
Clock Tower 3 for PS2: Cool game and freaky,although not as freaky as silent hill, but just took a break and got interested in something else.
GTA: VC for PC: After the missions, it gets boring. I didn't feel like doing stupid jobs to buy useless buildings. They don't tell you the useful ones, so I'd be wasting money for nothin.
Wayne Gretzky Hockey for N64: Last 2nd last team, had to return rented game.
Lamborghini 64 for N64: Sucked. Second half of the game is unfair.
Luigi's Masion for GC: Awsome game, but never finished because I was borrowing it.
I know there is more, but it's getting too hard to remember now and the list is getting big.