1) Go into the animation editor and trim the transparent edges off the objects. 2) Adjust the collision polygons for the objects. Move the platform's collision polygon up and/or the solid's collision polygon down. (They don't have to correspond exactly to the graphic.) 3) If you are using an invisible platform object with the visible sprite pinned to it, move the relative position of the pinned sprite down relative to the platform sprite. 4) Use invisible solid sprites and separate sprites or tiled backgrounds that provide the visual appearance for the platform.