Very interesting game concept!
The controls are very clunky and unintuitive, but after a while I was able to sort of figure out how to get around. The main gun seemed pretty useless since I could hardly aim my ship at all, let alone directly at the enemies long enough to hit them. Holding ALT doesn't seem to help with anything since it seems like it just points your camera and not your ship or guns. That left the missiles as my only actually effective weapon, which were still difficult to use but that meant running out of ammo became a second lose condition, which isn't great but at least there's quite a bit of it. Like others have said, the enemy AI and lack of an option to skip dialogue also weren't great.
The little model of Libestal in the middle is cute, but scaling it up significantly and adding a few more parts to the environment would probably have made it a little easier to navigate and made it feel a bit more like you're fighting in an actual world instead of an empty plane.
I managed to get pretty far into the Shiori fight but I gave up after a few attempts. I still had fun on this version despite the flaws, but with some improvements, it would be a really fun game!