Alright, fixed the underground section to be ~3-4 seconds overall faster, hitting the crate with the key earlier/faster, hit more ants, avoided all shots (except for falling damage in the waterfall thingy which is unavoidable), got a few more explosions in (you can shoot the ants' grenades out of their hands hehe), and generally improved everything.
Improved underground section Goldenwood WIP
One VERY interesting thing I found is that head shots (where the ant's head flies off their thorax) is manipulatable, based on what frame you shoot them, so you see more head shots in the underground section to prove this point. (and it saves bullets.) However, what is better is that for doors requiring triggers, an ant that loses its head automatically goes ghost without "suffering" which saves a lot of time. This is a huge deal, meaning door cans be opened much faster with all head shots.