I've played and completed it but not enjoying it.
It has coins in almost all rooms but that's all. Aside of scales and coins, the rooms are empty making exploration feel dull.
There's serious issue with double jump versus swimming. There's no indicator to tell if player could perform double jump or not after leaving water stream or water, making it hard to tell if player could double jump after that.
If those issues are fixed, this game could be better.