Glad that you're getting a chance to play around with it, and that it's working out well for you. There is indeed a lot of new stuff to explore. If you're feeling adventurous, you could start looking into the rule systems (Sprite Definitions and Plans) and maybe even the source code to see what adjustments, modifications, or even new developments you can come up with there. Springs work by a bit of custom code. Obviously not every game in going to have springs in it, and there is no intrinsic support for springs in SGDK2, but if you look at (I think) the source code objects, you will find the custom code that was added to this project in particular to make specific tiles behave like springs. But you can still have plenty of fun without getting into the source code, too.