You know what, not many people try to remix this song... like... almost nobody does... The only thing is, It doesnt seem like you remixed it at all. However, you did do a good job of replacing the instruments. other than that, its identical to the original. You should try to find a different piano VST. it kinda sounds like you're using FL Keys, and if that is the case, you can make it sound better by adding a reeverb onto it or changing the muffle and harndess knobs. As for note-wise, you should try adding other variations into the piece that make it different from the original and more your own. But hey, the more i listen to this, the more i want to go make a remix of it myself XD haha. I'll let you know how that goes.
Please contact me if you would like to use this in a project. We can discuss the details.