Furi is an outstanding title that has enormous potential for replayability. This rhythm-based boss-rush style game combines bullet hell and combo-based gameplay that will have you thinking about Devil May Cry, and Galaga at the same time. Oh, and the soundtrack is absolutely outrageous.
This is probably the most mechanically unique of all of the platformers on this list. In Owlboy, you play as an owlboy named Otis. This game is similar to Metal Slug, in the sense that you have a wide variety of weapons to choose from, but it differs in the theming and physics. This game is hard to explain, but it is absolutely worth your time.