Nice and addicting game! I was really close to finishing it! But here comes my problem with the game: The speed gets way too high after some time if you keep upgrading it, so the game actually gets harder instead of easier. Which makes the game also way more frustrating. I also wished some more balancing or more upgrades, since after 4-5 or so runs I just couldn't buy any more upgrades, so It was purely based off skill after a while. Also the graphics are a bit blurry, you can change that if you use unity by doing the following: Go into the file manager and click on the sprite, then select point (no filter) as the filter option, this would've improved some of your sprites drastically. I really liked how you implemented the roguelite concept into space invaders, really creative! With some balance and polishing I can see this becoming a great game! Good Job!
(also it would be cool if you could check out my game ^^)