Agree with other comments that sex on loss is a downer, I actually won first play and was wondering where's the lewd? An easy fix would be to unlock the scene when you beat the level and flash a message at the start of the next one. "Stage 1-1 gallery unlocked!"
As far as SHMUP balance, I think the stages go too long, especially stage 1 since there's no powerups and fewer shooters enemies. On the other hand the use of shielder and shooter enemies is a great combo given limited time, and it's an excellent touch that your shots can interrupt a shooter while she's charging.