OK, I've played this game quite enough now. Score = 498900.
I chose the top right ship, which was slow with the best charged weapon. On the boss battles I used the charged weapon to cancel out a lot of their projectiles. I made it to the third round 4 or 5 times.
I like shmups and this is a decidedly average one. Having said that, the handling and the gameplay was alright, and I quite enjoyed it in stages. As a result of playing this game, however, I have developed Nephophobia (fear of clouds)!