Frogun is okay, but the levels are a bit boring, and you have to redo them a lot if you want to 100% the game. Plus, the races against your rival are annoying because he bumps you around a lot but you can't do it back at him. At least, those are my memories from when I played the game several years ago.
Someone on 4chan /v/ made a texture mod that put pantsu under her skirt, but sadly I never saved it and have no idea where you'd find it now. (´～`)