Looks great, reminds me of SMW. If I can criticize anything, the rocks sort of stand out a little too much, but It's a very minor critique. Other then that, It's a good start and I hope you make more of these.
Yeah, I used SMW grass overworld tileset as a reference. Soon I may make more, desert one is likely to be next tileset as I have a cactus bgo gfx that been for some time so I might bring with it.