As requested, here's a WIP.
http://dehacked.2y.net/microstorage.php/info/3636/L2%20Boss%20Start%20%28-1489%29.m64
As for level 2, I wasn't able to make the jump, although I'm really really close. I'm pretty confident I'll be able to find a seam between polygons to jump on, when I actually get there (I was just playing around and experimenting with some save states earlier).
As for my run, I wasn't able to save much time after the 2nd key in level 3, but there really isn't a whole lot between that key and the boss. All in all it added up to about 2/3 of a second, although I did improve the last set of wall jumps a little. I think my column jumping might be able to be improved a little too, so I may go back and see before I seriously start on the longhunter. So, for total time saved, I'm just under 25 seconds. Lemme know if you see anything glaringly improvable.
EDIT: Eh, redid the jumping pillars sequence and saved 4 frames, but at least it looks a little cleaner, since I only do 1 turn instead of 3. I also saved a little time with a cleaner start down the hallway leading to the arena/pit, so now I'm ahead by just over 25 seconds (1502 frames).
EDIT 2: Got the first humvee done with a full compliment of explosive shells waiting for the second one, and great starting aim (not to mention half a second saved, which surprised me). I've worked my way through the second humvee twice now but I just can't get so that I'm happy with it. It'll get done sometime tomorrow.