Lately I've been enjoying a silly little co-op climbing game called Peak.
Working together with friends, your goal is to scale the mountain. You have a limited stamina bar that is constantly impeded by hunger, injuries, and a variety of other effects. Luckily, there's plenty of food and equipment to be found out there - just make sure not to eat the green crispberries. They might be a bit poisonous. Oh, and you don't want to carry too much heavy stuff either. Luckily, your friends should be there to help haul you up the last legs of difficult climbs.
The game runs great on Proton. We've had occasional issues with the built-in VoIP, but it's always been either "working perfectly" or "not working at all", which is much better than inconsistency. The VoIP is absolutely worth using, by the way - especially when someone falls of the mountain.
My only real criticism of the game is that there's not much to do if you get yourself killed. You return as a ghost to spectate the other players, so you can talk to your team and scope out paths a little bit. Otherwise you have to wait until they reach the end of the stage, where they can revive you. If you're patient, this isn't a real issue. But it can be frustrating if you get killed for a reason that isn't directly your fault, and some of my friends take issue with it. But IMO the fun of working together and the satisfaction of making the climb seriously outweigh the penalty for carelessness.
You can check it out on Steam: https://store.steampowered.com/app/3527290/PEAK/
