If you want to enjoy this game, you NEED to read the manual. Playing this blind is odious and how you need to play it is not as obvious as most other shmups.
The thing about having to crash against the bosses to kill them is interesting, but just as you would think, is very annoying to pull off since if you get hit by a bullet it negates the explosion and that's what's most likely to happen as you near the boss you're trying to attack.
The thing about the game entering sudden death mode when the timer runs out on the bosses, sure, it enforces the suicide bomb playstyle expected from the game, but will be an immediate turn down for anyone who, like me, came expecting a traditional shmup and didn't look for the manual. So, hopefully, you'll read the ♥♥♥♥ing game up. It still makes boss fights really annoying if you take too long to beat them, which is more likely than not since you'll spend most of your time running into bullets while trying to suicide into the boss. Hopefully this problem is solved once you give yourself enough practice and time to learn the game, I did not give myself that many.
One thing I remember from this game is that there were a couple patterns on ♥♥♥♥ing easy that did not ♥♥♥♥ing belong on easy.
One thing that bothered me a lot is that once you die, you get a short time to select a new character to send out, which you can select with the arrow keys. DON'T. Just ♥♥♥♥ing DON'T. If I want to select a new character before spawning, at least let it be only with the actual character selection keys. It's REALLY annoying when I set some character to be the next one to go out, and then when the current one dies, a completely different one is sent out because I didn't let go of the arrow keys or I pressed it too early.