In endless mode, Baldi gets faster overtime. So that means if you wait long enough, he will have SUPER SPEED!
I recorded this video showing how fast he can get:
in snowman's land, there is a tree at the top of the snowman. there is a one-up on it.
In Mario 64, some butterfly triplets will not only spawn a 1-up, but also bombs that if touched by Mario, they will explode. if not, then the bombs will roll around before exploding.
In Lethal Lava Land, near the log for the "red hot log rolling" star, the 1st platform you use to get on the log sinks in lava.
the baby penguin will also sometimes jump.
what? anyways, one thing i noticed is after you get the baby penguin back to his mother, sometimes he will do a little dive.
little details you never noticed.