Actually, I started casually working on this (again) about a week ago. It's a real pain to optimize.
I haven't found any glitches. I was going to put together a rough testrun, halfassedly optimized, and see what everyone thought before committing myself to it. I'm having the usual internet woes, so I'll post my test of the first 2 levels (same level order, I think?) as soon as I can, so you have something to compare to.
I wasn't going to collect ice balls or the Z jars in the test, but I imagine both would be useful, depending on where they were and whom the boss is. I'm not sure how long the Z jar lasts, but there's at least 1 level where it's in the boss room, if I recall correctly. If you don't have to go too far out of the way for the ice ball, and the boss moves around a lot, then go for it.
For the first level I play's boss, I don't think the ice ball is useful, but for the second, I'd say yes.
I can tell you that stabbing is faster than jumping, if you have to use Orin to get by an enemy. Otherwise, it's best to stun with Cutrus and run with Orin. Taking damage on stairs doesn't seem to slow you down.
I don't have lots of time right now to work on it, so I'm glad someone's taking it up. I'll play around and see if I can find anything for you. And good luck ;)
edit:
here's the levels 1&2 test
It's not optimal by any means, but I've tried out various strategies in various rooms. Maybe you'll get some ideas and/or see what not to do ;)
In particular the rooms that involve jumping are not done well.