In Square Enix's Gun Loco, the craziest criminals in the solar system have been banished to an abandoned prison planet where they engage in a blood-fueled race for survival and freedom.

And now that the game has been announced for Japanese release, guess who's coming with them:

Unfortunately, the Hatsune Miku virtual "vocaloid" idols aren't going to actually be in the game. However, their voices will make it in thanks to the Gun Loco Vocal Edit Contest that Square Enix announced today.

The contest has players create the vocal part for Suki Suki, one of the game's background music tracks. Instead of directly singing for yourself, though, you use Crypton Future Media's "Character Vocal Series" voice software to make virtual idols Hatsune Miku, Kagamine Rin/Len or Megurine Luka perform the song according to your own interpretation.

This contest is similar to a contest Square Enix announced for the US version of the game, although the vocaloid tie-up is of course new for Japan.

Interested in taking part? The contest is open exclusively to Square Enix Members who reside in Japan. If you meet these criteria, visit the Square Enix Members contest page to download the music, lyrics and instructions.

There's also a music sample at the page, if you just want an idea of what to expect.

Submissions are being accepted from today through October 4. Following an initial selection phase, Square Enix will let Square Enix Members determine the final winner via a vote to be held between October 18 and October 25.

The winner will get their work in the game and will also take home a cool ¥300,000. Second place gets an Xbox 360 250GB system and Gun Loco.