Maybe that's why I died so much, I never use bombs if I can in these games, even if I'm going to die, I didn't know they were required to be used... I never played Darius Burst, so I don't know how they managed to do that, but every design comes with a solution, so maybe that game does something that tells the player to bomb or it is implicit in the design in some clever way. So yeah, you could do like I did with Touhou just trying different things to see how enemies behave and the different tools the player has. In my case, most of the balance of the game didn't come from just enemies coming and despawning, but enemy armor and a damage cap to balance the player's damage as it progress, these were things I learned directly from Touhou, but there are definitely other ways to do it.