Pretty fun & simple, having some blocks would make it more challenging, nice job!

Fun! As someone already said, just spinning feels like the best strategy, but I personally wouldn't try to fix and just make it spin by itself.

Maybe having a bit less enemies but having two or three different patterns would have been nice.

Nice work overall!

It plays really well!

This is pretty fun early in the run, as time goes on though, it starts feeling like you're going to get better results just spinning than actualy trying to get anything specific done, so if suffers there, bit of a hard issue to fix though. I would attach a cost of some sort to sword movement, (or fast sword movement) and perhaps chill a bit on the enemies, so that you always have meaningful desicions. Maybe make faster sword movement have a cost or a cooldown.

Graphics were pretty nice, and straightforward, and the music worked well, a simple pattern, but layered with some figures on top that were frequently changing, even if often only with a bit of distortion or similar to stay fresh each time through. Sounds like the game music picks up around 1:30, and it sounds great, but I only ever heard that section for like five seconds at the end of a hold left run.

The shielding/blocking mechanic hasn't seen a lot of use lately, maybe most recently it would be kind of like the sword dome in dome keeper? Used to almost be its own little subgenre, I remember playing a typing game variant of this a long-long time ago, which I eventually remade (still a long time ago). So there is a lot you can do with the 'defend a stationary object' idea. 

I think the theme is reasonably represented here. The health bar naming is weak,as that's basically a story based element, and not what you would normally think of with enemies attacking the planet. You also, however have the player object being physically moved around on the screen by the ships attacking it, which really sells that they're knocking you around. A little wobble as your health gets lower would have sold it further, but not bad. (something in the neighborhood of rotation = 50 deg * missing health % * sin(time_accum), that sort of thing, if you dont' mind rotating sprites))

Congrats on finishing a game for the jam =]

fine gameplay , not really close to the theme