Good start!
You've got a good start for the making of a fun game! There are a few things I had problems with though:
- Depth perception was hard to assess at first. I was never quite sure which row I was in in relation to the objects that were approaching me. Traditionally there are 3 rows in this type of game and it took me a while to realize there were 4...
- The music fit the game, but got a bit repetitive. I know you had toggle controls for it, but I think that better music in general would have really helped out.
- The advertisement reappearing from time to time was quite annoying.
Otherwise, good job!