Half-Life 2 has had a lot of children, even if they're not directly spawned by the legendary juggernaut. Industria, a surreal, atmospheric puzzle-filled FPS definitely owes a lot to Valve's game, but it manages to carve out an identity all of its own. One of 2021's most underrated games it can now be yours to keep for free, but you'll have to make sure you grab it before this week's over.