Yoshi's Island: Super Mario World 2/Controls

Walking
Press or  to walk left or right, respectively.

Entering doors
To enter a door press.

Entering pipes
To enter into a pipe, press.

Jump
To jump, press.

Flutter Jump
After jumping, still in the air, press and hold.

Swallow and spit out enemies
To swallow and spit out enemies, press.

Aim and shoot
To aim and shoot an egg, press. To cancel the shot, press.

Ground Pound
To conduct a ground pound, press, and in the air, press.

Lay eggs
With an enemy in mouth, press.