I've noticed some wierd things about Jazz2(other than the usual).

Spike bolls can be shot of.
There's a couple of secret levels that were never used.
The secret level SECRET LEVEL (diamsecr.j2l) has a strange event called DON'T USE! in it.
The debris that falls when the queen boss stomps is actualy an enemy and can be stomped.
And there are lots of areas in the game that are impossible(without cheats) to get to.

There's probably more but I just wanted to tell you this.
Anything else?