According to ESRB, this game contains: Mild Cartoon Violence
Parents don't have anything to worry about. There is no sexual content and no questionable language. The only violence is on the level of bopping square-shaped monsters and harmless-looking robots. There is no blood or gore anywhere to be seen.
Platform fans might want to check it out simply for the reason that the PSP's pickings are so slim right now, but it's not good enough to hang with the big boys of the genre, or even that not-so-big boys. It has some appeal, just don't go into it expecting too much.
Deaf and Hard of Hearing gamers will do just fine. All dialogue in the game comes via text, and there are no important auditory cues or information. I played over three quarters of the game without any sound, and encountered no problems at all.