Ive encountered a few gems:

- Transistor: A masterpiece. The best soundtrack that ive ever heard and an amazing story. One of my favorite games of last year.

- The Swapper: Mind bending game, great puzzles, great story and very original.

- Bastion: from the creators of Transistor. Great game. I loved the voice acting and the tone of the game. Amazing art style.

- Apotheon: really good game. Got it with Ps Plus, never finished it but enjoyed a couple of good hours.

- Broken Age: From Tim Shaefer, great point and click game. Really good story and amazing voice acting. The art is also very beautiful.

- Child of Light: really good rpg.

- Never Alone: beautiful game. It shows you the culture of the Iñupiat people, i loved this game.

- SOMA: one of my favorite stories ever. Amazing ending. Really good atmosphere.

- Stick it to the man: really funny game. I liked it.

- Thomas was Alone: amazing puzzle game. Really humorous.

Dead Nation (Twin Stick shootem up zombie game)

I agree with OP: Dust if one of the best games I've played on the past 10 years. It's pure gold.

I'd add to the list the addicting Race the Sun, Never Alone and Life is Strange, which is pretty famous now fortunately.

Im telling everybody .. DL Spelunker world. Sooooo fun 6 player coop + free

Well, it's good but very simplistic and modest. It's a cute story and focuses on the bond of the 2 main characters. It's the type of game that you can love or hate, so it's hard to recommend. It also lasts just 3h or somethig. 

Transistor, Bastion and The Swapper, not much else tbh i don't really browse the PSN Store anymore.

The PSN is getting closer and closer to the shithole that is Steam, i'm getting sick of all this flash games that wouldn't be allowed in newgrounds 10 years ago filling the store with garbage.

Sound Shapes is a really fun platformer (and addictive too).
Thomas was alone was another nice platformer that I thought was really good.
And I agree with Dust:An Elysian Tale, not that many people gave it the attention it deserved.
There was also Monsterbag for vita, the art style reminded me of Fosters Home for Imaginary Friends and it was funny as well with some nice puzzles.

They might not be classed as hidden gems but for absorbing stories with good puzzles, Ether One and The Vanishing of Ethan Carter are pretty good. Ether One can be buggy at times but that is forgivable.

Xeodrifter

A Metroid-esque shooter/platformer. Very fast-paced and pretty difficult.

Helldivers. Most awsome unexpected small game i've ever played. Still play it today.