SD Gundam: Dimension War

Here are two japanese-only games on Virtual Boy, that despite some good graphics are pretty mediocre.
Things I forgot to mention: There actually are quite many action-oriented Gundam games... even if I've never come across any myself. You can't return to the game select screen when you've entered a game in Space Invaders, you have to restart the Virtual Boy. Not a big deal but a little annoying nonetheless. Oh and SD Gundam has a save feature.