
Ikaruga has been a difficult game to judge. The GameCube offers the best practice mode, aka conquest mode, which you're going to need. The Dreamcast version is the most arcade accurate. The XBOX 360 version has online multiplayer, and some even say that the inaccuracies are actually updates. And then you have the PC port with the least slowdown and multiple graphics options. So which version should you play?
Its easy for me to eliminate the arcade [sorry purists], since their are accurate ports with quality of life improvements. So here's what you do. Grab the GC version and git gud, then when you're done practicing grab yourself the Definitive Version on PC and blast away. From my research it would appear that the changes made in the steam version are intentional. That, in combination with the additional graphics and control options, gives it the edge.