Terrain deformation is persistant in savegames in spintires, in mudrunner is is not. Terrain deformation does vanish behind you after some time driving, probably to save memory, in spintires it does not. Mud has less deep geometry and the textures are all a wash, just compare mudrunner screen to spintires screens, the mud is 'nerfed' a lot. Result is the mud look bland and kinda the same in mudrunner maps. Mud options in editor are cut down from 3 or 4 down to only 1, means the map makers can only apply mud in 1 way and that is why all the mudrunner maps, the mud allways look the same, you can not do the cool stuff like in spintires anymore. The shifter was made more casual, where you needed some practice to shift rapidly in spintires you do not in mudrunner. You know, i was positive toward mudrunner before it was released, they could have made it better compared to ST, instead they did what they did.