Excellent game! At first I was a bit confused by the lack of jumping, but the gameplay was intuitive after a minute or so.
Graphics - Nice retro 8-bit look. Plays well. Has a bit of a "Minecraft" look to it, but is definitely a nice look for the game.
Audio - The song is nice, and the sound effects, while simple, are good. Only con here is that the music loop is rather short and should have the option to be turned off.
Gameplay - The gameplay itself is rather good. The wraparound mechanics and the no jumping make for a nice form of gameplay that somewhat deviates from the norm. Definitely good here. The simplicity of the enemies doesn't detract from the gameplay, either. It makes the game focused on timing and approach, rather than just reaction time and jumping around.
Overall - 9/10 - I gave a small ding to your score based on the lack of audio control. Besides that small complaint, the game itself is great and I would like to see more. Great work!