Here's a free game that's really clever. It's in a genre all of it's own. Takes 15 minutes to beat. I highly recommend it:

Dr. Langeskov, The Tiger, and The Terribly Cursed Emerald: A Whirlwind Heist: http://steamproxy.net/steamstore/app/409160/Dr_Langeskov_The_Tiger_and_The_Terribly_Cursed_Emerald_A_Whirlwind_Heist/


And if you like that, these same developers made a equally brilliant game called Stanley Parable, but this is a paid game (if you could even call it a game, lol): http://steamproxy.net/steamstore/app/221910/The_Stanley_Parable/

Here's some other puzzle games that I bought but haven't played yet:

Entropy Rising: http://steamproxy.net/steamstore/app/334830/Entropy_Rising/
ChromaGun: http://steamproxy.net/steamstore/app/408650/ChromaGun/
Parallax: http://steamproxy.net/steamstore/app/325060/Parallax/
The Talos Principle: http://steamproxy.net/steamstore/app/257510/The_Talos_Principle/
INSIDE: http://steamproxy.net/steamstore/app/304430/INSIDE/
TRI: Of Friendship and Madness: http://steamproxy.net/steamstore/app/293660/TRI_Of_Friendship_and_Madness/

Here's some fantastic puzzle games I've played:

Antichamber: http://steamproxy.net/steamstore/app/219890/Antichamber/
QUBE: http://steamproxy.net/steamstore/app/239430/QUBE_Directors_Cut/
QUBE 2: http://steamproxy.net/steamstore/app/359100/QUBE_2/
The Room: http://steamproxy.net/steamstore/app/288160/The_Room/
The Room 2: http://steamproxy.net/steamstore/app/239430/QUBE_Directors_Cut/
NaissanceE: http://steamproxy.net/steamstore/app/265690/NaissanceE/
Disoriented: http://steamproxy.net/steamstore/app/556240/Disoriented/
The Rodinia Project: http://steamproxy.net/steamstore/app/681520/The_Rodinia_Project/
LIMBO: http://steamproxy.net/steamstore/app/48000/LIMBO/
Portal: http://steamproxy.net/steamstore/app/400/Portal/
Portal 2: http://steamproxy.net/steamstore/app/620/Portal_2/

Great friend? YES