So I started playing this over the weekend at the suggestion of a few friends.
It's absolutely brutally difficult. PVPVE is the best way to describe it.
There are basically two factions spawned into a bunch of very large maps, PMCs and Scavs. PMCs are your main character, scavs are randomly generated characters with a hodge podge of gear. PMCs are always players, and scavs are a mix of AI and players. Objective of the game is basically to spawn in, gather supplies, and extract. You keep whatever you get out alive with, and lose EVERYTHING on you if you die (with one exception if you have a gamma case, you can keep a couple small items safe).
There is no HUD, no in game map, very realistic, you get popped in the face with no armored face shield... you're dead.
You can do scav runs 10 minutes after the completion of your previous scav run... so you can't just run in with no consequences constantly. You have to put your main character and their gear at risk. You can spawn in with friends, but there is no HUD as mentioned, so you need to keep track of your team. My buddy killed me twice our first three games. I made him drag my gear out and give it back during the next run.