Monster: ALL directions

First change the sprite to the "monster3_nice".

Start by adding the End Step event...

After hits a wall, let's first check if it starts going left...

• Going Left? If hspeed smaller than 0, then subimage "3"
• Going Right? If hspeed larger than 0, then subimage "2"
• Going Up?  If vspeed smaller than 0, then subimage "1"
• Going Down? If vspeed larger than 0, then subimage "0"

Make sure they all face the direction they're moving like this and get it checked off.