One of the best co-op games, and one of the few stealth co-op games, "Styx: Shards of Darkness" is 85% off (only $2.99) for a few more days, and the Steam Summer Sale isn't over yet, so it's not too late to put your spending money towards another game. It's not too late to put your spending money toward another game. Better yet, invite a friend to play with you.

I regularly complain that co-op campaigns don't exist like they used to, and Styx: Shard of Darkness, which I picked up a few years ago, was the answer to my complaints. The game is a stealth RPG in which you explore vast levels of darkness and crawling spaces, taking down guards and avoiding combat. The only thing you have to suffer for it are the bottom-feeding scatological jokes by snarky goblins.

If you got burned by the not-so-good creepy little guy stealth in "The Lord of the Rings: Gollum, King of the Damned Desert,"

, this should be your next choice, as Styx: Shards of Darkness received a high 79% review rating, but despite how easy it is for me to recommend, it maintains a shadowy, little-known status.

You can play solo if you want, but you'll have an epic time in co-op: as Styx and Clone Styx, you and your companion can each unlock your own skill tree and specialize in soundless stealth, trapping, alchemy, and enemy tracking. You can stick together for a double-kill, or split up and lead the way by dousing lights and taking down armored guards. This is one of the best memories I have of playing with friends over the past few years, yelling out clinch-move moments.

Styx can be under $5 a few times a year, but this $2.99/£2.69 is the lowest price I've seen; it's easy to play for 10 hours or so and easy to invite a co-op partner to play. The first game, "Styx: Master of Shadows," is also on sale for $1.99, although it is single-player only.