The best game you never completed...

[boost]

Battletoads, ldo.

But seriously, I don't finished most games. I played through a good chunk of HL and HL2 and then just kinda stopped, but eventually went back and played through both. With those two it was for sure worth it. I think I played HL2 all the way through a second time actually.

[swiggidy]

Battletoads, ldo.

My first thought. Some NES games were ridiculous hard.

"Finishing" a game now is harder to define. I beat Halo on the first 3 difficulties, but gave up on the next to last level on the hardest setting, so did I fail?

What else came to mind were games like Grand Theft Auto (3, 4, and 5) where I "beat" the story (which is easy), but only got to 80% complete where the last 20% was insane.