For a game with the status "prototype" this is extremely well polished. The graphics are great and the BGM is suitable and fun to listen to without being distracting. Sound effects themselves are great as well, especially the gun sound almost visceral. Gameplay is challenging but fair once you get the hang of it; I don't think I ever died due to anything other than my own fault.

Some criticisms then:

-Aiming seems a bit off every now and again. The aim locks into the direction in which you were last moving, though a dedicated button to lock the character into place whilst being free to aim in all directions would be great (similar to some Metroid games, for instance). The dedicated aim buttons that allow you to shoot in left, right, up or down direction wouldn't be necessary then, as these are unintuitively placed (at least on an Xbox controller, where the left thumbstick is used to move, but the D-pad directly below it is used to shoot up and down).

-It's unclear when you lose your shield and by what criteria, and I couldn't seem to retrieve it once I died. If there are armor-recharge/reequip-stations or whatever planned then it makes sence, but for now it seems kind of strange.

And that's about all really, I enjoyed the demo and definitely hope to see more of it in the future.