Read the review for a good generalization on the game.
CUSTOMIZATIONS! That is the highlight of this game.... you can strap just about any weapon to your androids body and i swear.... the weapons are freakishly cool I mean come on... who doesnt like a nice big rocket launcher jutting out of your head? You can customize the head, torso, arms, and legs all with slots of their own.
Story.... uhh.... was there supposed to be one? They obviously didn't try hard here but all the fun comes from beating the crap outta other robots in the first place so it really doesn't matter, though it would have been nice to see one.
Graphics: They could have worked on them a little bit like making your android stick out from the rest of them.... the level design graphically is a little mushy but the graphic effects that come from your gun are really the most pleasing to look at.
Now as this being the 2nd Rengoku I liked most of the elements from the first one and the little things that they did fix or change still make it a really fun and cool game to get into. You do not have to pick up the 1st game to play the 2nd.... not much point in it.... but none the less it is a game worth checking out on your own.