Here's the game description from its website:
Super Crate Box is coming to bring back the glory of the golden arcade age, when all that really mattered was getting on that high score list. Grab your baseball cap and loosen your pants, it's time to fight endless hordes of enemies and collect every weapon crate you can. Prepare for an arcade delight with interesting, refreshing game mechanics, cracking retro art and a terribly hip chiptune soundtrack.
The game is about surviving for as long as you can. Little enemy guys are coming from the top and it's your job to avoid/destroy them while collecting crates. Each time you collect a crate, you are given a different weapon, which makes the game very hectic and exciting. There are tons of unlockable weapons and characters so there's a lot of replay value!
Here's a screenshot:

Content: There's no blood, enemy sprites simply "pop" or fly off the screen when hit with a weapon. Basically, it's suitable for anyone who's comfortable with cartoon violence.
If you like platformers, fast action, or just are a retro game fan, Super Crate Box is for you.

*** Game Website ***