I say 3.5 Nothing that new or interesting, but it is an ok game to kill time. It's fun, but too short. I think a cool thing you could do, is add more upgrades, maybe some character customization, and different game modes would be interesting.. But yeah, all you have to do is just circle around and keep an eye out for stuff spawning behind you, and you win. It's that simple. Something you could do is add different enemies. Like ones that are fast, or zigzag, and stuff like that. Also, add some variety to the music. It gets annoying after awhile.