I like this alot.
I have a small criticism for the sound design which is you put alot of detail into showing the force of the Bullet Bill but the catching noise was pretty soft, which does show mario's stength, but also makes it seem too easy/less impressive.
What I might suggest, to have as little change in terms of animation as possible, is at 5 second mark when Mario catches Bill by the nose during the cut to black/whiteimpact, is use a rubble or rock shattering sound, and then have mario be unscathed, but all the force was transferred onto the brick that her is standing on leaving him in an impact crater holding bill.
It helps play on the expectations, and demonstrate mario's stength in a way I think would be more impactful to an audience.
Other wise I really like the way you drew bill and mario, especially with Bill's frustration at having been caught, and the cannon really showed great motion.
Thank you for making this.