Could be much better.
It looks decent at first, but I quickly notice some irritating aspects about this game. Ignoring the fact that this game is pretty much yet another Mario clone, here are the things that could be improved.
Firstly, the stones are pretty much useless, because they arc over your enemy whatever you do. So you try, over and over again, and what happens? I run out of stones just at the moment I thought I'd hit it. Might as well stomp your enemy.
Secondly, the graphics are deceiving, especially the log-shaped platforms. That means most of the time, you fall through! This gets even worse when you try to approach a platform from an angle.
Thirdly, I'd say the sound effects are decent but some are a bit out of place, especially those that play when you stomp some enemies. Those Koopa-like things, would you expect to hear a crushing noise when you stomp on them, when in reality it just retracts into its shell?
Overall, I'd say this is a decent game, but could be way better if these problems were addressed.