Thank you :D The second stage is impossible. It is not complete and I left it in by accident. Glad you finished the first level though :). I'm currently working on another game jam that I hope will turn out better!

Set the mirror on the platform with the blue gem to blue and set the mirror on the platform with the red gem to red. Then left-click on the first/green mirror and then on the mirror that is now blue. Then click Space. If you walk to the right for a while you should go into the blue mirror and at the same time come into the red mirror (because the red mirror clones the blue one). Lastly, you should be able to walk out of the red mirror and walk into the red gem.