Helmet aside I'd like to see:
1: The biceps extended by a couple inches to make them more accurate.
2. The top contour of the rear thighs to come higher. There is way too much black showing.
3. Rework the chestplate so the pecs smaller and higher.
4. Make the cog on the backplate look more defined.
Use the Devcon 5 minute epoxy. Not the plastic weld just the normal epoxy. Also make sure you sand the surfaces that are going to be glued, this makes for a better bond.
I understand bloopers don't count, but Mr. No Stripes was not a background trooper, had quite a bit of screen time in multiple scenes, and was used in a promo poster. As a rule of thumb, promo posters tend to be perfect.
I'm still suprised no one has tried it with Mr. No Stripes. He is in the movie, promo poster, action figure photo, and the origional action figures had no stripes either.