I'd like the sprite's vertical motion to be automatic: It ought to move from the level's bottom to the top of the screen, with the player only able to steer it left and right. Holding the Pressing down arrow should slow the sprite, and the upward movement resumes once the down arrow is released.
I have 8Direction enabled to provide left & right motion, but that's as far as I got.
I tried giving the sprite a Bullet behavior and setting the angle to 270 but that seems to disable the ability to steer left and right. One tutorial I found had the sprite sit still while the background and every other object, granted a Bullet behavior, shot downward, creating the illusion of forward motion, but I'm hoping to avoid this and to truly have the sprite moving upwards always and gliding left/right only when arrow buttons are pressed.
It's not an endless runner: There is a finish line to cross, if that matters.
All help appreciated.