I'm rather sad that there's quite a few SMB2J tiles missing (namely the ground, underground palette tiles, 1-3 platforms etc). Would it be possible to add these?
On another note, the "tree-platform" (the ones used in 1-3 in SMB) have a little shadow added to the top of their tiles making it look strange when stacking them like they are supposed to be.
..Also cool would be having SMB/2J clouds and SMB bushes, just for consistency.
..But anyways, good job! I really like the tilesets so far and can't wait for the next set to be implemented (as in, the ones that are posted here but aren't in the beta). I especially like the 8-bit tiles that were upgraded to 16-bit, great work!