He's smokin' entry plug, he's on that LCL.
He's got 4 knives
Stupid sexy Eva
*sort of, not a gundam but it's a kit by bandai so... 
As someone coming at this from 40k, honestly pretty impressed with the kit. All snap-fit, with full articulation? Multi-colored sprues? Hell yeah, let's go. Really need some finer grade sandpaper; I had to make do with just a glass file which is a bit too block for some parts (and doesn't work at all for the metallic parts because it makes them way too shiny).
Only a couple things went wrong during building. The right metallic pectoral cover is loose for some unknown reason (I may have filed down a ball-joint too much?), and the left purple bicep cover doesn't rotate which means the rest of the arm likes to pop off if I'm not careful. There's a noticeable gap on the fingers in the left hand on the first image, and I don't know why since there were no sprue connections ono the surfaces that connect to each other.
Might put on some more of the stickers but the one on the entry plug is already peeling so idk it might be wasted effort. Also the kit came with two spare knuckle covers that I don't see a use for in the instructions.
Full kit name is "RG ARTIFICIAL HUMAN EVANGELION UNIT-01"
idk if it would help in this specific case, but i have successfully used plastic wrap to tighten ball joints, just wrap the ball with 1 or 2 layers of plastic wrap before attaching the part, maybe more layers if its still loose. if you are careful you can pre-cut or tear off excess plastic wrap so its barely even visible. Bandai models usually go together pretty conveniently, i have some allegedly 'snap-fit' maschinen krieger kits i paid upwards of 60-80 USD for each one, where there were gaps on almost every seam and none of the parts fit together great, i even had a polycap joint split in half somehow. i trimmed with clippers and a knife instead of sanding tho.
Luckily the part that's popping off isn't the ball joint itself, but a different stationary part that the ball joint is supposed to hold in place, so in this case I'm just going to glue the stationary part down. Thanks for the advice though!