I'll admit, I've never played JJ1, though seen a lot of footage of it. The tiny resolution combined with the high speed makes it look frustrating. I'm not fond of trial and error.

I kinda prefer the soundtrack, however it does have its share of boring tracks.

Asides from that, JJ2 brought features that kept the community going. In specific, JCS and online play. JJ1 does have its own editors, though they are unofficial, which makes those who played the game less likely to know about it.