The first thing I thought when I started the game was the filter and brightness make the screen too hard to see, but it turns out the contrast between the bullets and the background is on point, so it's no real issue. However, the enemies could stand out a bit more. In terms of gameplay, it's a good CAVE-like shmup and I had fun with it. Finally, this is a matter of taste, but I'd rather have the bomb make you invincible for a couple of seconds and be shorter than up your firepower.
Some bugs: the game returns an error on start-up since the asset directory and the .exe file have different filenames. Changing them manually fixes this. In the settings, the "windowed" option seems to do the opposite of what it says. It also freezes my game, but that just might be a Wine issue (I played this on Linux).