Crimzon Clover: World EXplosion. Top 3 shmups of all-time and best shmup on Steam, IMO.

Absolute favorite is Outer Wilds. The only thing I don't like about it is that I can't experience it again. A true masterpiece of a game.

After that, probably Noita for sheer insanity. Deeply unfair, but getting a god-run going is that much sweeter. It took me ~100 hours to beat it the first time, now I can consistently win if I try but I'm addicted to doing stupid things to see what happens.

Stardew Valley

Anything of Soldak - https://store.steampowered.com/franchise/soldak/ : 2 series - space shooters Drox and hack n slash Dins - Super coarse graphics, action, fighting, but their living worlds, like nowhere else. No other game where worlds freely grow based on player actions. Did You ever left main quest for exploration, lvling up or side games, oh well, here, world will not allow You to, as enemies won't stay idle or wait for You, they do their business.

Orb of Creation - https://store.steampowered.com/app/1910680/Orb_of_Creation/ Semi-clicker (intense clicker, not much of idle) and immersive mage simulator, where You don't make Your mage-avatar, but are the mage. Still beta, but already big.

I suppose I've plugged it recently, but Another Crab's Treasure.

It opens pretty plainly as an ocean-based Soulslike parody with a simple story premise and some self-subverting humor in the dialog with other crabs. As you go on though, every 20th conversation becomes really pointed and real-world-connecting, going beyond just "pollution bad". It's not quite Spec Ops: The Line, but it at least has something to say about society.

The combat is frustrating but addictive, much like Souls games - and it's okay with handing off a number of allowances like accessibility modes and tip systems. It's even helpful that, if I die to a glitch or something bogus, I can actually just choose to re-obtain my microplastics (souls) through a menu.

Sticking only to ones I haven't seen mentioned:

• Tandis : geometry puzzler
• Gateways : a 2d portal-style puzzler
• Elliot Quest : pixel adventure
• Phoenotopia Awakening : also a pixel adventure, had trouble with the final boss but the rest is great
• Wuppo : flash-animation-style comedy adventure
• Alba : sweet game about a girl who loves wildlife
• Salt and Sanctuary : 2d soulslike
• Legend of Grimrock : tile-based first person dungeon crawler ("dungeon master" spiritual successor)
• A Short Hike (really short but amazing exploration game)

Ones I have seen mentioned but can't bear not to mention:

• TIS-100 : the finest of the Zachlikes; a programming puzzle game
• Crosscode : 2d adventure with incredibly fine-tuned combat and puzzles
• Outer Wilds : fantastic time-loop puzzle
• FTL : space adventure "one more run!" game
• Slay the Spire : deck-drafting "one more run!" game

Factorio, hands down

600 hours and counting. The space age expansion basically quadrupled the content, and is the first time I've played the game 100% vanilla with no mods in probably 10 years. Great times.

Rimworld

Celeste is one of my favorite games period, and it qualifies. The gameplay parallels the story better than any other game I've ever played or seen played, and the soundtrack, art, and characters are amazing. Top tier gameplay and a great story to go with it.

Alternatively, if you're looking for absolutely unhinged strange gameplay made by a programmer rather than a game designer, check out Fractal Block World. It's pretty fascinating!

Super Daryl Deluxe

That game has one of the best soundtracks I've ever heard in a game.

Synthetik is my top steam game with, like, 900 hours.

Magicraft.

Minecraft (the old one)

Banished, you can't get more Indie than just one guy's passion project.

I don't know what it is about that game but it really struck a chord with me and I've come back to it over and over. It's my favorite game to play when I'm sick and can't do anything. It's relaxing and peaceful and cozy while also being complex and ruthlessly challenging at the same time, so it's like spinning plates. Seems easy when you get the hang of it but it can all come crashing down if you make a bad enough mistake. It's spawned some copy cats, and I've tried them, but the original just gets me somehow.

Can't really add much to all of the great games already mentioned. But I'll add one, because it was one of the best games I played in recent memory. Chants of Sennaar. Where to even start? Point-and-click adventure/puzzle game that is all about language puzzles. With great visuals and music. Really dig the eurocomics inspired style. I don't know why, but this game really touched me - maybe it's because the game is about uniting people in an age of discord.

Some I really appreciate that I'm not seeing on this list:

I'm currently enjoying Blue Prince which is a fairly new rogue-like puzzle/mystery game it's hard to explain without spoiling but it's worth looking up.

Portals of Phereon is one of my absolute favorites. It's a fairly deep tactical RPG thing with loads of replayability. It's kind of like a Pokemon x FF Tactics but with monstergirls and it's also currently free while it's in development. Be aware it's extremely NSFW and horny, which I suspect is the main reason it's not as popular as some of the others listed (IE rimworld, stardew valley, etc.) however the horny is such a key point to it's original gameplay and world-building that it wouldn't be the same without it.

Thea: the awakening is a decent tactical RPG. I love it for it's original battle mini game, crafting system and world-building. It unfortunately has some balance issues and jankiness that prevents it from being an all time favorite, but it's definitely one I would encourage at least trying.

Thought of a few others:

• Reus (2nd one's alright, first one's excellent)
• Library of Runia
• Book of Hours
• Kenshi (saw it listed one other time, but it deserves a lot more love)

Just looking though some of my higher playtime games, here's a few I haven't seen mentioned: (I think they're all indie or small studio)

Gunfire Reborn - Roguelike fps with infinite replay.

Troubleshooter Abandoned Children - XCOM style battle system with a really really fun way to customize how your character fight. Story is pretty lame though (I ended up skipping it) and it's pretty grindy.

Thronefall - Pretty challenging base defence.

The last spell - Turn based base defence with lots of different ways to build your characters.

Ratropolis - Roguelike real-time card strategy base defence. Pretty good, although not well balanced at highest difficulties.

Swapper

Not my actual favorite, but it's very high on my list, and I didn't see it posted yet.

I really liked What Remains of Edith Finch.

It was more of an experience and really struck some emotional chords, leaving me write emotional at the end.

Really beautiful and melancholy experience.

Check out Tunic. I would recommend going blind.

Used to play battlefield 2, BC2 and 3 alot. Then I stopped playing online games and recently started playing "Ravenfield". It's succesfully filling the void, there are even battlefield maps and some vehicle/heli/jet/tank mods and ignoring the fact that it looks like battlefield heroes (very indie-style graphics), the physics/handling feels pretty close, especially when flying heli and shooting rockets

The vast majority of my favourite games have been listed, many multiple times, so I'm gonna go with some I didn't see, though I didn't look exhaustively, here we go:

Horace

Quite a hidden gem in my opinion, almost no one I mention it to has heard of it. 2D platformer with an amazing story and some interesting gimmicks. One of the most surprising and unforgettable indie games I've played.

The Messenger

Ninja action-platformer that is way more than it first appears if you stick with it. Hilarious writing, great controls, and amazing music. Genuinely one of my favourite games.

Yoku's Island Express

Almost entirely unique in it's idea. It's a pinball-metroidvania where you're a postman dung beetle, and it really works. Gorgeous world, super chill vibes, clever puzzles... What metroid prime pinball should have been.

I have a personal soft spot for Doki Doki Literature Club because it got me into programming when i was young, but that's far more sentimental and to be honest i wouldn't play it again as an adult really. If i had to pick something functionally though I'd say Project Zomboid. there's a fuck ton of fun to be made in that, especially with Multiplayer. Even in singleplayer i like to turn on a NPC mod and assemble my own makeshift Walking Dead cast

Dyson sphere program is still one of my enduring favorites.

Saw someone else out urquan masters, so I'll put Caves of Qud and Rain World. they both of some of the best pixel art ever, and caves of qud has some the most dynamic story telling in anything I've played

Slay The Spire

Fury

Ori And The Blind Forest

Undertale

i'm not sure The Ur-Quan Masters counts as indie

Factorio.