Dear ootc, thanks a lot for your feedback, it's really appreciated! ;)
I'm just working to add check-points,. I'm also trying to find a solution to the "Star-Attack" problem. Do you have any idea about how can use the Star without violence?
PS: I'm also working on the 6th level (with portals)
PPS: from today Pinghetto is available on the Google Play Store: https://play.google.com/store/apps/details?id=org.godotengine.pinghetto