Besides the already mentioned ones, here are some that i finished and found them fun games, all with interesting boss battles and non-rpg.
XG Blast
Lunar Knights
Megaman ZX 1 & Advent
Donkey Kong Jungle Climber
Sonic Rush and Adventure
Viewtiful Joe
Meet the Robinsons
Nanostray 1 & 2
Ninja Gaiden DS
Pac-Pix
Pac'n Roll
Space Invaders Extreme 1 & 2
Big Bang Mini
Dragon Ball Origins
Metal Slug 7
Time Ace