While nearly identical in concept to Konami's Dance Dance Revolution, so much so that Roxor has been sued for patent and copyright infringement, some conceptual differences can be observed: the use of mines (which reduce one's life if triggered) and hands (a third or fourth arrow needing to be hit by slapping the panel with your hands), a scoring system based on the percentage of points scored over points possible, denser step patterns (some songs have over 800 steps, whereas DDR's densest song has only around 600), and a heavy emphasis on arrow modifiers present in the game's mod-heavy marathon courses
Just to let you know, I play both ITG and DDR. I'm not a fanboy of either. I like them both the same.
equally retarded ITG fanboy: wel, in teh groov is mor orijinul and haz betta sonz n stepchartzz!!!!!!!!111one!1111three
Me: You're both retarded. Both games are good. DDR is just as good as In the Groove.
Friend: Oh no, they put In the Groove in the cabinet.
Me: Don't worry, Konami will sue the hell out of them.