im watching through the run, currently at sonic and i have a few ideas on how to save time
1 - using CPU easy i believe is faster as the CPU's dont give as much resistance (like yoshi) 2 - avoid Movement Rushes, they waste a lot of time 3 - also avoid Full Stun Strikes. while the time penalty isnt as severe for base marios FSS then other characters, it still loses time to racking up damage normally. if you find yourself stuck in one, then purposefully fail one of the commands as it skips the slowdown at the end (before mario hits with his hammer) 4 - avoid hitting any of the other koopa bros. it isnt easy with mario as his hammer has long reach but killing one of the other koopa bros loses time. try your best to avoid them as they cost precious frames 5 - down Z is slow, so attempt to avoid using it unless you're sure that it'll hit (or if the combo breaks and the opponent is guarding as you've been doing) 6 - you should start the shadow battle by blocking (or running, jumping, then blocking to get closer) as he might use teleport strike immediately 7 - turn on CPU emotions in settings, it becomes way easier to gauge what actions they may perform with it on, which makes sudden decisions easier to make 8 - avoid using pursue if you arent sure it'll hit. base mario isnt using his blue bar for anything else but it loses a bit of time if you whiff
i am no mario main, and i apologize if this comment sounds rude but its all in the spirit of saving frames