Splosion Man, Ms. Splospion Man, The Maw (not a side-scroller), Blade Kitten, and Shadow Complex (more shooter than platformer), most of the early Oddworld games, and finally THE GAME I FUNDED: Giana Sisters: Twisted Dreams.

Thanks everyone for all the suggestions I bought him The adventures of shaggy and he likes it a lot. plus I got many games wishlisted.