So I'm currently in my third year of my game design/graphics education, and during last spring we started working on the game Scrap Pirates, which is a sidescrolling platformer where you use magnetism to overcome challenges in the levels. And it's got co-op support!
A lot of time has gone to other parts of the education, planning etc. so far, but we've started making progress again in the production and we're getting ready for a reworked test release in a few weeks!
But fear not, there is still an early version that you can try out right now!
So head over to scrappirates.com/ and check it out, leave your e-mail if you're interested, and any feedback would be very appreciated