Very nice execution! This is a really polished game--everything feels well-oiled and professional. This is the third shooter that I've played so far, and it definitely is the most satisfying of the three. The teleport mechanic was neat, though to be honest it didn't really feel necessary; I played for a little while but never really felt like I was in any significant danger. I think the biggest thing that I was missing was something that increases the difficulty over time, like faster bubble movement.
Oh, yeah! Nice audio, too. The music was pleasant without being distracting, and the sounds for shooting and hitting a target were satisfying.
Overall, probably my favorite of the small handful I've seen so far.