In my memory, X4 is absolutely excellent. Returning to it, it's...not that, but it's not bad. It's something of a return to the series' roots in terms of gameplay scope, with pretty simple, straightforward levels and a lot less stuff to track down. The cutscenes certainly impressed at the time, but coming off of X3 I was really missing a deeper experience, and the levels, while straightforward, are often kind of boring. Playing as Zero is pretty neat, though. It's a very playable game, and it looks nice, but I'm not sure trading a longer, more interesting game was worth the tradeoff for the CD-era presentation.