Which ones are the underrated and overlooked games on Steam?

Underrated or overlooked? I know quite a few games which tend to be overlooked, but most of them have a decent rating on Steam.

FTL, Transistor, Bastion all great games that don't have the attention they deserve.

Cool, I added a few of those to my wishlist, they look nice.

Some underrated games that I really liked:
Yesterday - Point and click adventure with a great story
Mars: War Logs - Nice sci-fi RPG that plays a lot like Witcher 2. Lots of fun if you can look past the terrible voice acting
I Am Alive - A very cool take on the post-apocalypse thing. Story is pretty meh, but good game.

The Long Dark? A very peaceful and early access that will not be abandoned.

To sum it up, you were flying mail in cold, snowy Canada when your airplane engine shuts off and you crash below. You are then to survive the harsh conditions by searching around for food and supplies and by taking shelter.

• And Yet It Moves
• Floating Point (it's free to play)
• Dishonored (yes, I know it's very popular, but I still think it doesn't get the attention it deserves)
• Dust: An Elysian Tail
• Blackwell Franchise
• The Treasures of Montezuma 4
• Mark of the Ninja
• World of Guns: Gun Disassembly
• F.E.A.R. Franchise
• One Finger Death Punch

Also multiple obscure point-and-click games. There are a lots of those.

Gomo. That game is hilarious.

Aquaria Got a bit of buzz around its release, but I've not heard many talk about it since. Really good underwater metroidvania-ish game.
Delver Deeper Has been bundled a few times, but I've not actually heard anyone mention it. Fun little turnbased strategy game with a nice theme. Easy to pick up and play and does not take all that long to finish.
Dominions 4 Well known in certain circles, but it seem to be quite unknown outside of those. Excellent turnbased strategy game with more content than you can shake a stick at. There are literally several thousand different unit types in it.
Eversion Fun twist on the old cutsey 2D platformer formula.
Kohan series Really well made real time strategy games that play unlike anything I've played before, or since.
Battle Academy series Quite good turnbased tactics games
Pandora: First Contact Overshadowed by Civilization: Beyond Earth, Pandora is actually a far better game in many regards. It's not flawless though, and once Beyond Earth has received ~2-3 expansions, chances are that it will be the better game, but for now, Pandora is the way to go (if you don't have Alpha Centauri, or have played through it several times).

Type:Rider
Mark of the ninja
Remember Me was good, though it deserved its knocks on its gameplay
Dreamfall, so far so good, though a little buggy at times graphically
Guakamelee
Primordia
Republique
Year Walk

Just bought Magicite this recent sales. Totally worth it.

Blackwell games
Silence of the Sleep
Edna & Harvey

I'm writing these games directly from my library. (:

Alice: Madness Returns - I still think it's underrated. It's a long, sad journey through Alice's mind.
Alpha Protocol - It's buggy as hell but still worth multiple playthroughs. It's made by Obsidian after all. (:
Angelica Weaver: Catch Me When You Can - It's one of the best hidden object games I've ever played. And I played a lot of them. (:
Bad Bots - A short (2 hrs) side scroller that worth it's price.
Before the Echo (formerly known as Sequence) - A brilliant rhythm rpg game. The setting, characters and dialogues are awesome!
Bleed - Another short side scroller that worth it's price. It has great mgame mechanics (like quad jump)!
A City Sleeps - A bullet hell rhythm game made by Harmonix. Keyboard controls a bit clunky but you have to play this if you like rhythm games.
Contrast - Great platformer with great setting. Also great soundtrack!
Cthulhu Saves The World - It's funny, it's challenging and it has Cthulhu... as a hero!
Distance - A survival racing game with great visuals, soundtrack and Steam Workshop support! It's in Early Access now.
Hexcells & Hexcells Plus & Hexcells Infinite - Great puzzle games. You should definitely try these!
Jets'n'Guns Gold - A great SHMUP with incredible soundtrack made by the friggin' Machinae Supremacy!!
LYNE - Another great puzzle game.
Master Reboot - I'm scared to continue and it's not even a horror game!
Receiver - A gun simulation. No, really.
Rise of the Triad - I don't know why but this game didn't get any press coverage as far as I saw.
Sakura Spirit - "There are fox girls in it. And you can play it with one hand." ~ A Steam Reviewer
Sang-Froid - Tales of Werewolves - That soundtrack alone is enough to refer this game.
Secret of the Magic Crystals - Because why not?
Sigils of Elohim - A free, tetromino puzzle game made to promote The Talos Principle.
Skullgirls - Crowdfunded 2D fighting game. It's great!
Spectraball - A decent platformer that makes you a ball.
Symphony - A virus affected your music collection and you must purify them by making them a SHMUP and use the power inside them. (:
TRAUMA - A decent art-puzzle game. You might wanna get it at a sale though; it's short.
Type:Rider - "A typographic odyssey."
The Typing of The Dead: Overkill - It has "Football Manager" and "Shakespeare" DLC's. And you can activate as many as you like!
Vector - A running game (like Canabalt) with great animations. Check it out.
Velvet Assassin - A guilty pleasure of mine. A clunky stealth game with "meh" story but it has its moments.
Wrack - A DOOM-style, fast paced FPS with cell-shaded visuals. It's worth a look.

And I'm exhausted... (:

Bit.Trip saga.

Marlow Briggs and the Mask of Death

+10 for Marlow Briggs. One of the most funny games on steam, no-brains hack n slash that came out of nowhere with no pr.

Theres a bunch of multiplayer ones that are mostly dead but didn't deserved to. Mean greens, Lead and gold... The ship isn't dead but the small community shows how little its recognized- and despite the years since release(and the sequel) it remains as fresh and unique compared to all the other multiplayer games - and better then the almost copy-cat version ubisoft made of it for assassins creed.

i rly enjoyed fieldrunners despite it having few/mixed reviews

I was gonna post, but I posted one year ago, apparently. :P

I would say War of the Human Tanks, as it has a very interesting and fast paced strategy mechanic, which cannot be found in any other game, the most similiar would probably be the Advance Wars series, but those games are not and probably never will be on Steam.
On the other hand I can very well understand why it many people would shy away from the games as on the surface the premise looks like the worst weeb shit many (mainstream) people have seen.

Hollow Knight
Wand Wars
Candle
Shift Happens
Ultimate Chicken Horse
Mushroom 11
Livelock
Seasons After Fall
Human Fall Flat
Push Me Pull You
Unbox
Poi
Crashlands
Clusterpuck 99
The Deadly Tower of Monsters

Underrated and overlooked definitely

I don't think English Country Tune is getting as much attention as it deserves.
It's the most relaxing thing to absolutely wreck my brain I've encountered so far.