You don't have to use a bullet behavior at all! I tried making a game similar to this and here is how to do it... so give it a platformer behavior and put default controls to no. Now head to your event sheet and do the fallowing events...
sprite.x < player.x
---- sprite: simulate platform pressing right.
---- sprite: set not mirrored
sprite.x > player.x
---- sprite: simulate platform pressing left.
---- sprite: set mirrored
Also if you want him to jump over stuff do this...
is by wall on left
---- simulate control jump
is by wall on right
---- simulate control jump
I hope this helped!!!