I personally bought the game on the day of release. I was not expecting much from this game but after playing through it I was really impressed.  The whole idea of the game is based around the idea that you are a pilot and have just saved the entire universe from the enemy aliens.  so it is basically a side scrolling shooter which you would think that that would be pretty self explanetory. But here is the twist, suddenly the whole universe goes out of wack and you have to play the whole game backwards, to repeat you actions in reverse to save the universe again from a paradox.  The story isn't pushed on you very much since it is simplistic and not very important to your enjoyment of the game.  It is told to you through mission breifings in the stage select through the campaign.  The backwards concept to it really makes the gameplay unique to it though.  You have to dodge enemy attacks coming from the left to the right so that they go back to the enemy and recieve your own attacks going from right to left at you. You do this to avert a paradox.  all this to the beat of the awesome chip/beat mixture of this games amazing soundtrack adds up to a hectic and enjoyable time. It has a rockband /guitar hero vibe to it as your shot that you recieve intertwine with the beat of the music. Also playable with the guitar accesory used for rock band.  I played it with the regular controller and thought its controls would be better suited for the fast movements required for this game.  And this game can be really hard on the higher difficulties.  This is not a problem because one of the biggest pleasures in the game is to go through the levels on a really high difficulty.  The campaign itself will only last you at most a couple of hours. But the meat of the content is found within the challenge mode and unlockable features.  The challenge mode is huge it basically takes the regular stages and puts a certain rule for completion on it. These range from harder ones like complete the level 120% faster or complete the level without any mistakes.  To just plain awesome ones like complete the level with disco mode on!  Now there isn't many different types of challenges, so to keep things from getting to tedius and boring they put unlockables into the challenges so every once in a while you will unlock something.  these things are artwork and songs from the sound track which can be acessed through the extras in the menu.  They also have cheats and different ship skins to use things like the minecraft ship and big head mode usable in the stages. There are dozens of these in each category through the extras, and they are given out at just the right pace to keep the player going.  And yes disco mode is available as a cheat for all the stages!  This has truly proven in my opinion to be one of the gems on the ps store that have been rolling out lately.  So for 10$ go out right away pick this up and enjoy the disco! You won't regret it.