This might be a slightly unusual attempt at a prompt, but might draw some appealing unusual options.
The way it goes: Suggest games, ideally the kind that you believe would have relatively broad appeal. Don’t feel bad about downvotes, but do downvote any game that’s suggested if you have heard of it before (Perhaps, give some special treatment if it was literally your game of the year). This rule is meant to encourage people to post the indie darlings that took some unusual attention and discovery to be aware of and appreciate.
If possible, link to the Steam pages for the games in question, so that anyone interested can quickly take a look at screenshots and reviews. And, as a general tip, anything with over 1000 steam reviews probably doesn’t belong here. While I’d recommend that you only suggest one game per post, at the very most limit it to three.
If I am incorrect about downvotes being inconsequential account-wide, say so and it might be possible to work out a different system.
Infested Planet
RTS. Kind of reminds me of the ground comabt from Star Wars Empire at War crossed with Starship Troopers. Command a squad of space marines tasked with battling an overwhelming alien horde. Pretty fun campaign (if a bit of a predictable story), plus an endless mode. Not exceedingly difficult, but definitely challenging enough to make you think tactically and keep you on your strategic toes. Somewhat limited replayability makes the sticker price hard to recommend (unless your bread and butter is RTS), but it regularly goes on sale for less than $5, which it is absolutely worth!
Reminds me of Creeper world except faster paced and more dynamic.