Hi hello, for a first try this is great. I'd be proud of this if this was my first attempt at an edit. You pick good sync points and have nice, creative ideas for a game that's hard to do new things in.
One thing that stands out with this video is that the keyframing could use a ton of work. Sony Vegas is difficult when keyframing pancrop/effects compared to After Effects, but it's doable with some extra effort. Consider toying with the different keyframe "effects" such as Smooth and Slow, and be sure to have some sort of keyframe interpolation so that it looks less stiff.
The focus on the tori by blurring uke in the first replay was really soft (and quick), some people could watch this without even noticing it was there.
Velo had the right idea, but the project's FPS is really low to begin with. Try to avoid choppiness when slowing down replays, maybe use twixtor. Slowing replays down where there is less movement allows twixtor to blend frames without too much morphing, since they're similar.
The masking at :33 is a good idea, I see the inspiration from slykuiper. It looks incredibly static, perhaps some sort of animation can fix that and make it look nicer on the eyes. The choppy slowmo is super important here, these kinds of bits of an edit are the parts that you want to "wow" people with the most. I would consider spending more time on making a scene look great when doing something like this. I'm too lazy, so I don't bother.
Don't be afraid to get closer to the toris with your freecam. This might be personal preference, but having the toris at a static distance from the camera (at least with all the slower parts that we see the most) looks really bland, and the colors/shader don't make up for it. Pancrop is great, but it's pancrop on top of a great shot that looks great. Magic Bullet Looks is something to try for color correction, at the very least curves within SV can improve an image a ton.
The white flashes could be done by using a layer set to "add" above the video, using solid white and fading it in/out. This'll work well for the time being until there is some better understanding on keyframing here.
I'd consider asking around for some help as well. Luigizinhu, perf, Glimpsed, and Hours are all still around (i think). They probably have better things to tell you, seeing I haven't edited any Toribash in years.