According to ESRB, this game contains: Animated Blood, Violence
Parents shouldn't be too concerned about any risqué content. There are a few gooshy-looking aliens and theres a lot of gunplay, but nothings really too explicit or disgusting. The thing you should be wary of is the game's difficulty. It's far too demanding for children and will lead to instant frustration.
Action gamers will find an ego-crushing amount of action here, although the disc is quite short once you master the patterns of avoiding enemy fire. Up until that point, it can be extremely tough, and the Normal mode is a bear to finish due to the chintzy amount of lives and continues.
Contra fans will want to check Shattered Soldier out. It definitely lives up to the standards set by its progenitors and will feel like a real trip down memory lane. As long as you don't expect much besides what Contra has already achieved in the past, you won't be let down. I have a hard time recommending it at the full retail price of $50, though.
Hearing Impaired gamers will have no problems. There is full text accompanying all dialogue and there are no significant auditory cues.