Jordi, not sure if you are working off of this sprite sheet or nt. The walking animation for moving up & down the screen should use the 4 animation frames used on the second line. At the moment it's usiang the full walking animation. All the graphics are at https://drive.google.com/file/d/11aC0llrYiodmPT4fZDVPjV28SLCZdjck/view?usp=drive... should you need them.