Very nice puzzle game. It plays good and the levels are clever.
I had few issues. The ramps are confusing. You can just drive up any incline in the game, but to me the ramps blend in with the background. I was jumping them up like they were stairs, always took me a moment to realize I don't have to do that.
The tutorial was little confusing at the end. You have to throw the magnet up the green pipe to finish it, which made me think you need to do this at the end of every level. I was fixating on that quite a lot and was sometimes even planning the solution based on the fact that I need to get my magnet back after I get the key to finish the level. Which obviously you don't need to do, so the levels are often impossible to solve with both key and magnet in your possession.
While we are on that topic, selecting levels by aiming and throwing the magnet is too much of a hassle IMO. I wish it was simpler, just pressing a button on a prompt would be nice.
And last, unless you are planning to give R and W some separate function, please make R the default reset key (why is it CTRL ?) and bind jumping to both SPACE and W. Thanks.