OK after some quick experimenting.. I was getting 500-600 FPS with this version. Then I set about deleting each particle emitter one by one starting with the asteroid particles and the frame rate only went up around 50-100 FPS. Eventually I deleted the background glittering stars and my FPS shot up to 2000+! So... that emitter was causing a huge slowdown. I disabled the effects on that layer and it runs at 2000+ FPS so that's where the problem was... at least for me.
Try removing those effects and see what your FPS is