Really great effort on this one. It's so faithful to the original, it becomes a game of "spot the difference" to see how this game is different from the original (I wasn't sure if there was something different about movement and momentum or if it was just me, I seemed to trigger a spring slightly easier, and then the obvious stuff like lack of boss and swigining platform). I liked some of the fun additions like spin dash, and actual level transitions, and overall blazed through it having a fun time!
Great work, and the open source part just makes it even better!