I attempted to run your game, and unless I do it from Command Line, I get a WSOD (White Screen of Death?).
Slick’s pretty easy to run with and it comes with a lot of stuff that can be helpful to you, like the various stuff for controlling the frame rate, etc. And it has an extension for the lovely TWL GUI system, which can make a lot of things easier.
LibGDX is a personal favorite right now, mainly because I recently got myself an Android phone and it makes writing/testing things for the Android easier than trying to dig through LogCat. However, learning its built in UI system can lead to some fun do to the dearth instructions and the like (Though, just reading the sparse Javadocs and the actual code can teach you a lot about it).