REVIEWING
Ok, in the beginning, that rain sound is too loud. Its distracting... The piano is kind of off key... It doesn't all match up well... I don't really know how to explain it, but if you connect the phrases, it doesn't sound good. Lol, nice thunder.
The rain leaving is kind of sudden. Might want to make it fade out for a while. Ok, a modulated sine, sounds like something I used to do... Its note at 1:30 is horrible. Its offkey... Infact, most of this song is offkey, try and keep it on a key, so it fits together, not just a mess of notes.
Drums are a bit sudden, and by the time they've came, they've left, no notice, not build, its really sudden, it needs to be smooth. The song doesn't really feel full at all. It has like 4 instruments the whole time: Drums, piano (OBVIOUSLY synth), that sine, and the rain.
My advice... don't use piano. Leave the real instruments to the real world, use synths, because that's what computer artists use. We have so much power, yet we use it on making something that already exists.
The end is way to sudden. You need to work on transitions. Also add reverb to the piano, and maybe delay. That would make it sound much cooler, and fuller.
Overall 7/10, 4/5.