I think that you're right there Rustyspoon (Misha).
I actually uploaded the same WAV file to Soundcloud and Bandcamp, yet on playback, it does appear to sound different on Soundcloud. In fact there is an element of distortion and clicking here and there.
I also uploaded an mp3 of the song to Reverbnation which sounds better than the Soundcloud version.

The 16 bit WAV was mastered at high intensity using the LANDR app.

I can only deduce that it must be down to the way Soundcloud processes the file before presenting it.