SteamWorld Dig is currently available for free on Steam, and this Windows, macOS, and Linux metroidvania action/adventure is yours to keep if you snag a copy by midday Thursday. The game boasts well over 5000 "very positive" reviews, so it's fair to say the Steam world digs SteamWorld Dig. Here's a refresher:

Set in a western steampunk-inspired world, you control a robot named Rusty, who embarks on a journey to uncover the secrets of a long-abandoned underground town. As you dig through the earth, you’ll gather resources like ores and gems, which can be used to upgrade your abilities and tools to help you go faster and deeper...

But don’t think it’ll be that easy! As you descend into the depths, you’ll encounter a variety of enemies, environmental hazards and puzzles that will put you and your trusty pick-axe to the test.