Great game! The UI and tutorials helped make the controls intuitive and the art and sounds were really nice.
I got stuck for a bit on level 8 before I realised that blowing the goblins up doesn't lower your rating. The portals were a little annoying since there was no way to tell where they would go without trial and error as far as I could tell (Fast forward was helpful though.)
The level designs were great, I especially loved the cloning mechanic in the last few levels which made for some really clever puzzles!