TRy basically any launch title...

Almighty-mints

Sorry bud, but you're wrong on this one. Perfect Dark Zero and Dead or Alive 4 are just a couple launch games with very HARD achievements. The launch games had what I'd call "experimental achievements". That doesn't mean they were easy.

Oblivion.

I can think of others, but Oblivion is the clear-cut winner for me.

Retail: http://www.achieve360points.com/forums/showthread.php?t=104496

Arcade: http://www.achieve360points.com/forums/showthread.php?t=66950