Replaced upper arm with higher quality model (original on left)
Replaced finger tip with higher quality model (original on left)
Added elbow joint with broken half for end sequence
Modeled that goddamn screw
Taking some inspiration from the shitty model kits I have around my desk, I added lines/ridges to the Old Robot model to make him look a little more 'put together'. Some of the parts just barely fit together, leaving pretty noticeable gaps between pieces.
To contrast this is a nicer model kit, where most of the visible lines are a part of the character design and not a consequence of lazy/cheap toy design.