The Hip, shoulder and ankle sockets are loose but I would not attempt to replace them. I recommend using a little hot glue on the end of the ball and push into socket it will tighten up so can be posed with your other Figures!
Hot glue doesn't damage joint and can be pealed off and re-done as needed. Such a cool looking figure to discard because of a few issues. Will look great in your collection as it did in mine. The item "Hot Toys Aliens Alien Warrior MMS38 1/6 Scale Figure Used Condition USA Seller" is in sale since Saturday, August 29, 2020.
This item is in the category "Toys & Hobbies\Action Figures\TV, Movie & Video Games". The seller is "plzseltome" and is located in Southgate, Michigan. This item can be shipped to United States.