After hours of poring over memory addresses in the original SMB and SMB2j, I've pretty much figured out exactly how all aspects of player physics work in both games (except the wind in SMB2j, that still seems pretty much random). You can see a complete guide to it (770kB, 800x6,000px PNG) here. I'd like to see a few things implemented better in SMBC; mainly stopping/skidding and air physics, and I wanted to see exactly how they worked in the original games before saying anything. If anyone has any questions (other than how hex works), fire away. I'll probably come up with a similar guide to enemy physics at some point in the future. EDIT: Check it out, here's a guide to SMB3 physics as well, for the lulz! (300kB, 600x3800px) EDIT: And here, a supplemental SMA4 Luigi physics guide!