This is a pretty good moveset, but I feel as though there are a few slight tweaks that could make it better.
1. The SMB2 Crouch Jump is kind of weird. It feel like it'd be better to make the normal Crouch have a charge, then add more height to the Backflip if the ability is charged.
2. You forgot to add update_air_without_turn(m) to the Spin Jump, which is preventing the player from being able to control its direction in the air. Also, I feel as though it'd be better if it was floatier like the Long Jump and the airborne version just made you Spin Jump without the Jump like in Sunshine. Alternatively, you could keep the Air Twirl the same and replace the Spin Jump with a Twirl Jump.
3. Some speeds (both horizontal and vertical) are a bit too high. The Speed Cap in vanilla Mario 64 for Diving and Long Jumping is 48. The Air Dash and the Ground Pound Slide Boost in this mod are around double that. The Ground Pound Slide Boost also boosts you a bit too high vertically, since the default Slide Kick height is 12 and the Slide Boost is 30, meaning it's 2.5x higher. The same goes for the Kick Boost (which is nearly 2x higher), the Ground Pound Jump and SMB2 Jumps (which are above 80, well above the normal max jump height of 69 [the Triple Jump]), and the Ground Pound Dive (which has a vertical height of 22 [compared to 20] and a horizontal speed of 58, and though it's not that much of a difference in this case, it's still noticeable). To compensate for the reduced stats, you could make some of these states redirect your momentum in the direction of the control stick.
4. The Cooldown Timers for the Twirl, Ground Pound Slide Boost, and Air Dash feel unnecessary. I feel it'd be easier to make them work like the Double Jump.
5. I feel like the Kick Boost is a bit backwards. It should only work on the ground, but it feels like it only works in the air.
6. For some reason, you can't Double Jump after a Wall Kick, Ground Pound Jump, or Spin Jump.
7. The Wall Climb has a very slow animation and feels a bit awkward to start. I feel as though it would work better as a Wall Run that allows you to transition straight from a Run into climbing up the wall, kind of like those purple slopes in Super Mario World that allow you to run on walls.
8. Another feature I feel would improve flow and is easy to implement is the Dive Hop from Sunshine, which allows you to Dive from a Dive Slide to chain Dives multiple times in a row (kind of like the Kick Boost).
9. The height of the Air Dash varies depending on if the A button is held down or not.
10. This is more of a vanilla Mario 64 issue, but there are some states where you can't Dive or Ground Pound when you should be able to. For example, you can't Dive out of a Backflip, Ground Pound out of a slope jump (ACT_STEEP_JUMP), or do either when jumping off the top of a tree or pole (ACT_TOP_OF_POLE_JUMP) or jumping out of water (ACT_WATER_JUMP). It'd be nice if you were able to use those moves in those states.
