I played the first build through the tutorial and it is a good set of mechanics, the buttons took a little getting used to, but I got it in the end.
I liked it so downloaded the other build that came after the submission and gave the game a go, its a fun game, the enemies spawned a little much from the start so I died a few times straight off the bat, but that's just some minor game balancing.
Couldn't quite get when I could or couldn't use the shield from the damage it was taking or my own health, but those are some simple UI upgrades with a little more time.
Good job on this game it was fun to play.