It was weird how it got boring at first, because it was too easy. I was actually glad when it became more difficult. It's quite a nice game. It can take awhile to get good, but it always will! The music was fine too. It was just crazy at how many different kinds of enemies there were.
I managed to last until Level 22 on Survival. I kept getting achievements, but they didn't show up. I don't know if that's how they work. You hear the same laser sounds over and over. It was really big, but still quite good.