Hybrid Heaven/YMMV

Cult Classic: Despite its copious flaws, Hybrid Heaven is fondly remembered by a small group of former players, and not just because it was one of the few RPGs on the N64. It bizarre hybridised action/turn-based combat system with its incredible collection of moves (that allows you to give an alien a German suplex then curb-stomp it while it's down) remains completely unique in all of gaming. It was also, for its time and system, quite technically impressive (despite some bland level design and occasionally clunky controls) with fully-voiced, lip-synced dialogue in some of the cutscenes.
Special Effect Failure: Using the Expansion Pak. While it does make the game look more crisp and sharp, the Nintendo 64 simply couldn't handle how the game used it (high resolution textures being a big culprit) which causes the frame rate to suffer. What makes it more infuriating is the Expansion Pak was designed to allow games to have a higher draw distance and screen resolution, which would have been perfect for the game if it was utilized properly.