Difficulty:
EasyThere's very little challenge to this mission at all. The boss - a giant Crab-spider can be killed in a single shot to the face with a rocket launcher, if you have one.
Alternatively, just pack some shotguns and a couple grenades.
Strategy: Shoot the red lump/muscle on one of its legs until it collapses. Now equip a grenade and get close to its face. Push
when you get the prompt to toss it into its mouth. Do this twice and you have a weak point to fire on constantly.
If dodging is an issue then stay close to the middle of the lift and keep your distance.