So, time for some graphics feedback:
-Grass and Leaves are somewhat too bright. I'd recommend darkening those a bit for a more 'natural' look.
-Logs look a bit weird. Maybe intersperse those vertical lines with some shorter Diagonal/horizontal to make them look more like bark.
-Stone and Ores look good. However, if you have some lighter pixels, etc. in the stone, you should probably put the same in the ores(at the moment it's all the same shade of gray except for the ore itself.)
-Last point: would you be able to easily add a background? the purple doesn't look right
Sorry if I'm a bit OCD about this... I'm insanely picky on pixel art. Feel free to ignore any of what I said, though. This already looks pretty nice, so I'd focus on the game mechanics first