Inspired by the recurring topic every Steam sale over at /r/GameDealsMeta:

• What are some lesser-known Steam games that you recommend?

• Are there any genres you’d like hidden gem recommendations for?

If you're interested in previous Hidden Gem topics, you can find them here.

For popular recommendations and general purpose sale discussion, please use the main Steam Sale topic.

An update for this topic: I've always used the number of Steam reviews for a game as a rough proxy for the game's audience size. It's not perfect, but it works well enough. Steam effectively made this canon in one of their recent sales. They had a Hidden Gems category and then broke the game list out into different tiers based the number of reviews each one had. I saved their taxonomy so I could use it here.

Feel free to tag or group your recommendations based on these if you like:

All the categories above, except for the last one, are how Steam defined their different tiers. I have some qualms with them using "Cult Classic" there, but I'm going to follow suit for consistency's sake.

I myself added the last category, because I think there are plenty of games worth mentioning with more than 1000 reviews that still have a solid Hidden Gem vibe but have since found bigger audiences and "graduated" from the label.

Edit: This community is amazing, thank you all for all of your suggestions. Feel free to keep them coming. I have a Google doc full of ideas with my comments that I'm going to drop on him. I was trying to respond to everyone and then discovered that Tildes will rate limit you. So if I don't respond to you, I'm sorry but I definitely read your comment and checked out your suggestions!

My friend suffers from depression and lives 6 hours away from me so the happiest I see him is when we are regularly gaming together. The problem is that I haven't been able to find a game we both wanted to play for a while.

I just cannot get into all the survival crafting games that seem to dominate co-op gaming these days. I am looking for suggestions for anything else. Also, it needs to be an online co-op instead of a couch co-op.

His computer isn't the best so that needs to be a consideration, nothing wrong with older games. Ideally we are talking about PC games on Steam.

Examples:

• we played a ton of Risk of Rain 2, probably the last game we played a lot together
• we have played through Halo co-op a bunch of times.

Who has ideas for me?