I like the look of the game and what I saw also was fun. But I just walked to the left in the beginning of the game, defeated two enemies, and then there was a dead end. Also I was unable to go back to the previous area, which is why I am a bit confused.
For the menu: you should take the log of the sound scaling, because dB is a logarithmic scale. In other words: small changes in your sound setting, change the sound massively.
Still Cool Game!