So moving on in the Advent Calendar of classic games is Vectorman for the Genesis.

Released in 1995, Vectorman is a Sci fi shooter set in a post apocalyptic Earth where a rogue machine has taken over leaving Vectorman to save humanity.
The game is unique by it's graphical capabilities for such a 90s console game as much of the cast use pre-rendered 3D models, it really gives Vectorman it's unique identity.

There was an attempt to bring it back early 2000 which fell through.

Pros
Uses the Blast Processing Sega promised well.
Slightly quirky with it's secrets.
Uses it's setting well.

Cons
Can play a little awkward with mechanics
Enemies take a million hits to takedown
Criminally short

Verdict
Underrated in my opinion but I can see people getting frustrated with some of the mechanics