Questions about Andrew Powers + other

Why didn't Andrew Shoes ever come apart after Running as Ultraman?His Sneakers would smoke,But never come apart.Also,If Andrew was Invenurable,Why was he able to be pushed down?I would think he would be stand still & not move.Unless he was just trying to not blow his cover?The one thing i never understand are his Girlfriends,You would seen them once & never again.Like his first one Jennifer from School,You would think even after she was mad at him for lying,That he would still be bumping into her at school & maybe make up?Even if you didn't get the same Actress,You can still get the same Character to return.I know these must be Obsecure Questions,But i liked this show,So most people never heard of it,So this is my only shoot