The face on the figure is excellent.
I've never built my own figures from scratch but I have modified a fair number of 1/35 figures to suit my own purposes, it can be very tricky.
** PLEASE NOTE the information supplied below is
not a personal attack, it's meant to be
constructive criticism to help you improve an admitted weakness **
The right shoulder on your figure is a bit wide; with shirts/coveralls that have a vertical shoulder-sleeve seam the slope of the shoulder joint is a little way in from the seam, so the seam actually hangs down onto the top of the upper arm. The image below gives an idea of what I mean & also shows what creases look like, yours are too few & too smooth;
The wide-shouldered stance is also highly unlikely, below is a more typical stance for a mechanic using a hammer;
Sometimes it just takes putting in the effort to get it right, as you so obviously do with everything else, & a couple of decent reference pictures can't hurt.