My overall take of the song is it lacks any diversity, and it definitely has room for more instruments, your use of chip sounds and effects are decent. Really though the song lacks any emotion, highs, and lows, try improving there and of course you could always add in more instruments such as drums, bass, growls, strings, piano, theremin, etc.
You could've had a pretty good song if you built up the song more after the start, maybe have the frequency start becoming really fast until it sounds like you are holding down a note. Or maybe have a part in the middle where the beat carries you emotionally such as a repeat with a slight modification of 0:40 later in the song with a drum beat in the back. If you redid this in the right way it could be really good.
K4Music 
