Cool game, but here's some things I noticed:
- The audio got a bit too loud when multiple orbs fired at the same time. This could be fixed by adding a bit of pitch variation and adding a audio limiter.
- The shield doesn't point towards the cursor, which gets really confusing some times.
- As Sundler said, it would be nice if we could see more of the screen.
With that said, I think that, with a bit of polish, this could be a very fun game.