Also on OSX, I had a crash killing an enemy at some point.
Other than that, this game was really enjoyable. The upgrades kept me motivated and the rocket felt quite nice to handle. The gameplay is certainly the strong point of this entry. But it could get a little boring waiting for new enemies to arrive.
The graphics were really appropriate for the gameplay, as was the sound. But both of them didn't really stand out to me.
I suppose the theme wasn't tackled that explicitly, which is a bit of a weak point for this game.
But overall, I'd say that you did a very good job on it. It's an enjoyable way to spend 15-20 minutes.