PurpleSun | [TAS] SMG2: Cosmic Cove GS3 in 3xA Presses [Mario] @PurpleSunTAS | Uploaded 4 years ago | Updated 2 hours ago
The A presses are:
#1: Sideflip up the bubble-spawning walls
#2: Wallkick up those walls
#3: Backflip up from the first platform in the 3rd area

This run also takes a death to remove coins, which would save an A press in the post-star textboxes.

The key trick in this level is weak shake water jumping, where, as you can spin out of water by shaking at the surface, you can also jump out by lightly shaking the Wiimote/Nunchuk.
To help with this, there is also jump state storage, as well as long jumping out of water by jumping and pressing Z at the surface.
By holding Z or sliding into water, you store a long jump state or sideflip state respectively, and can do these jumps out of water, and can combine them with weak shaking to get long jumps and sideflips without pressing A.
You can also weak shake at the surface and press Z on the same frame to long jump, which is what I do to grab the star.

Luigi can already do this 2xA, but it is good to get an idea of what Mario can and can't do. This was previously 4xA as Mario, so an A press was 'saved', that press being long jumping to the star.
Luigi can skip the 3rd A press with some spin knockback jank, but I have no idea if Mario can do this and there's no video of the strat to show how to do it.
But it may actually be the case that Mario can do this, and the 3rd A press that was previously counted was in fact getting over the spiky plant after the wallkick section, which would mean Mario is also 2xA for this level, and ties Luigi for GS2 (2xA) and the second regular star (3xA) as well.

Also, at the start of the level, I went to the icy waterfall to get bumped up into the air, which removed hard landing state, allowing me to control the spin knockback used to bounce on the Li'l Brr.

#SuperMarioGalaxy2 #AButtonChallenge