The higher levels (4+) still need balancing. For example in both playthroughs (on version 1.15) where I reached level four the enemy for every gun I had would have 2-3 for every shield I had they would have 4-8 for every thruster they'd have 3-4. in one play through i was at level four and i only had 1 shield and 2 above normal guns one of which I literally couldn't use because I didn't have enough power for it. This game is really fun and you've been very on top of patching it but when the enemy can literally destroy all my projectiles and still have enough firepower to to shave off a couple blocks or when all of my guns firing at once can't even get the shield 2/3 the way down that's a tad overpowered and takes the fun out of playing.