The idea of controls getting harder as the player's health goes down is actually a brilliant idea. The only suggestions I have would be as follows:

1. Re-make the game in GameMaker Studio or Unity. While, yes, UE4 is amazing when it comes to 3D games, and our goto for 3D development, they absolutely suck when it comes to 2D games. We personally prefer GameMaker Studio for developing small 2D games like this, since the workspace is actually super convenient once you work it out, and Game Maker Language is arguably the second easiest programming language out there, second only to scratch.mit.edu xD. And, while it doesn't seem like such a big deal, I can tell you right now that just by playing your game, I could tell it was made is UE4, which isn't a good thing. Do yourself a favour and get Unity or, better if you can afford it, GameMaker Studio.
2. Use free-to-use assets that you can find online. There's absolutely no shame, but it does a lot to improve the quality of the game very quickly. Our submission was made almost entirely from one free-to-use tile-set from online, and the visual quality speaks for itself (granted, the level design isn't the greatest at times, since we were making them at 12am-2am lol). No matter how much effort you put into the art of your game, there's no denying that there's probably a free-to-use version out there that's better...

As picky as I might be sounding right now, I still genuinely think that this is an awesome concept and quite a fun game! It's just the small details that can seriously take this from being mediocre to amazing.

Was a fun game with an interesting concept, the mechanics created funny moments like being hit once, trying to dodge a bullet and accidentally flying straight into another spaceship.

Would love to see it fully fleshed out