1. The X-Com Files
The X-Com files is a mod for the original X-Com: UFO Defense. For people who've played the Long War mods for the new X-Com games, it's very similar to that. You start from humble beginnings, directing a rag-tag group of agents that die if an alien so much as breathes on them. Every action counts, since even having an agent turn around to look behind them costs action points. The game also uses proper bullet trajectories, meaning that any obstacles (including your allies) need to be taken into account.
A brutally unfair game that will kill your team before they get a chance to act, sometimes literally since taking a single step can trigger every enemy to fire at you. Knowing when to retreat becomes half the battle, and utilizing everything at your disposal is a must. And just when you think your safe, just when you think you've gamed the system, some Olympic level athlete throws a grenade halfway across the map, killing your elite squad of agents that you've spent 5 hours training up, forcing you to rethink your life choices. All of this comes together to an experience that genuinely feels like your fighting against all odds to save the world. And with so much content to boot (I have hundreds of hours, and I've probably barely touched 5% of the content within the game), this game easily earns the #1 spot for on my list.
2. Rain World
Having grown up playing flash games, each game brought a new world to explore and new rules to learn. Over time, these rules start to repeat, the tropes became stale, the genres started to blend together, and the unpredictability was lost. Rain World brought me back that sense of exploration and discovery. From enemy A.I. that actually feels like it's hunting you, to the gorgeously stylized alien world, to Slugcat, the protagonist of the game, who's design left me devastated every time they died, Rain World made me both curious and afraid every time I discovered anything new, fully capturing the essence of trying to survive in an alien world. I haven't felt that immersed in a game since my childhood, and as such it earns the #2 spot on my list.
3. Star Control II
Space Opera is one of my favorite genres, and Star Control II is the best in the genre. Explore the galaxy whilst engaging in epic space battles and witty space politics. Find allies to join your cause and free Earth and the galaxy from the iron grip of the Ur-Quan. From scottish pterodactyls to a race of mollusks that are afraid of everything, Star Control has a plethora of clever alien races to engage with. Each race feels fleshed out, both culturally, and biologically, and played a fitting part in the galaxy's politics. There is a whole galaxy to explore, secrets to be found, and friends to be made.
4. The Midnight Walk
I don't often buy games when they just come out, I usually wait for a sale or buy it bundled. The Midnight Walk was an exception. The claymation artstyle captivated me at first glance, and I knew i had to buy it then and there, and it was well worth the money I spent. The models are gorgeous, the world is interesting and well laid out. Often I would have to pause to just take it all in, and it would look like I had taken a frame from some claymation movie, it just had that cinematic touch to it. The only thing this game suffers from is relatively dull gameplay, but makes up for it with everything else. It had me inspired to try and make some models, currently learning to sculpt the old fashioned way.
5. Enter the Gungeon
(Work in Progress)