Half rhythm based and half shoot-em-up, Retro/Grade is the bastard result of leaving Guitar Hero alone in a romantic room with Galaga on a starry night, a lot of champagne… and potentially acid, as well. We’re not too sure. And all the while, the space-time continuum just happens to be falling in on itself right outside of the grimy hotel window.

No, really.

Retro/Grade, the bundle of intergalactic joy brought to PSN by indie newcomer 24 Caret Games, is the Shepherd’s Pie of concepts – a bunch of ingredients that no one in their right mind should put together, yet somehow ends up being not only edible, but delicious as well. A side scrolling shoot em up timed to music that can be played with either a guitar controller or normal d-pad, and manages to keep your head bobbing all the way through? Color me intrigued.

The opening cinematic of the game begins by having the player fire a single shot to end the climactic boss battle and immediately rolling credits. While it may fool you for a moment, the credits then speed up and suddenly evaporate into a primordial black hole of names and titles, only to be spit back out and rewinding with the urgency of a VHS that needs to be kind. The player watches the big baddie boss once more, again having no control over the ship, until just moments before the anticipated bad guy battle and everything starts working backwards down from the perfect score you achieved in that last detrimental blow. Suddenly, the shots fired at previous enemies are hurtling back towards you, and now the object of the game is not to kill the final boss, but to make sure that every shot you initially fired throughout the game is “unfired.”

Retro/Grade then throws you for a loop, as not only must you unfired the blasts you originally shot as you rewind through time to the beat of the music, but also avoid the previously-missed-and-now-timewarped enemy fire that you initially dodged from the opposite side. Don’t worry. Retro/Grade sounds more complicated than it plays, due to all of the the timey wimey factors involved.

In addition to the fun quirks, such as playing backwards through a perfect score and maneuvering your ship through the path it once took, another well thought out feature of Retro/Grade is the time reversal power up.

Since you’re already moving forward through the timeline in reverse, you can “rewind” certain objectives by using the fuel you collect for your rocket ship. This allows the player a quick retry for certain sequences that were not mastered the first time around, and a Game Over occurs when the continuum takes too much damage to sustain itself and collapses.

As lovingly crafted as the gameplay is, the area where Retro/Grade really delivers is it’s shiny soundtrack, so masterfully designed that even the rhythmless can stay on the same beat as the dubstep bumpin’ Captain Rick.

Once you get over the initial gameplay, Retro/Grade does little to deliver on new challenges and at times can seem to be simply a dizzying bunch of trippy lights and pew-pew sound effects. Adding together the smaller annoyances like repetitive challenges, no Platinum trophy, and only 10 songs means that Retro/Grade‘s fresh take can become spoiled rather quickly.

Despite being a rhythm based game along the lines of Guitar Hero and Rock Band, Retro/Grade pales in comparison to the more adult forerunners of the genre. While it is a fun game with an inventive concept to put in the quick rotation mix, Retro/Grade is one that probably wont stand the test of time or replay value. Nevertheless, for the music and intriguing system, it is definitely worth checking out for only 9.99 via the PlayStation Network.