Ahead of its appearance at PAX later this week, 24 Caret Games has posted a new trailer for its time-bending shooter/rhythm game hybrid Retro/Grade, which was a finalist in both the Design and Audio categories at the 2009 Independent Games Festival awards.

That initial IGF prototype has changed a lot in the past two years, and this video shows off the game's new visuals, new perspective, new music, and more, building on an already awesome concept: play a shoot'em up in reverse, dodging enemy shots bullets behind you while catching your own shots, manipulating time to undo your mistakes.

24 Caret Games will show off Retro/Grade at PAX booth 3008, giving out posters, info cards, and even a shirt if you can beat a specific challenge. It's also running a contest in which the gamers with the top five scores using a guitar controller and the top five score using a DualShock 3 will receive their name in the credits.

Retro/Grade will release on PSN some time in 2011. You can find more information on the title at its official site.

[Via PlayStation Blog]