The update was submitted to Apple by developers Vlambeer once the game's playerbase had collected a total of five million crates.
The "5,000,000 crates update", as Vlambeer are calling it, adds five new characters for you to unlock, including familiar faces from popular indie games and iOS titles.
You can also now select which character you want to play as from the game's Stats menu.
Vlambeer have also made some tweaks to the controls: Jump & Shoot is now possible, and the option to switch the A and B buttons around has been added for those who don't get on with the default layout.
Finally, Vlambeer have hinted at a future update, reproduced in full below:
One of our heroes has been kidnapped and 40 million crates have been demanded for her release!
Help us out rescuing her so we can stop worrying about that and start worrying about getting you a new goal for us to unlock more iOS-exclusive content & features!
Super Crate Box's crate count currently stands at almost 24,000,000, so we may not have too long to wait for another update.
If you're keen to muck in and help, Super Crate Box is available to download from the App Store for 69p / 99c.