Change the pixel size to 8 instead of 16 this should help if you add blocks like half slabs and would stop the player from floating inside the ground.

"Change the pixel size to 8 instead of 16 this should help if you add blocks like half slabs and would stop the player from floating inside the ground." when I said pixel I meant cell. super(width, height, cell size);

When you grab some 'sand', it first says you have 0 of it, then 1, then 2, etc. Just add one to the value to display. And this truely shows potential! I hope you're still working on this to turn this into a full game.

Also, when restarting, it doesn't load anymore. I looked at your code and this what I think is the problem: In your method generate (in your Bg class), you call the method height at some point. Only, in height you also call generate, causing a forever loop of calling methods, which eventually causes the stack (some part of the memory, where also the data of methods is stored) to overflow.