Man, this decade was full of great games I played. MGS4 and Dark Souls especially left a mark on me.
But if I have to go with one title only, it has to be this.
I'm not into platformers usually, so getting Spelunky as a gift from a friend, I had little expectations.
Color me surprised that it sank its teeth into me like no other game before. I'm at 700hrs now and the only reason it's not higher is because I had to force myself stop playing it after over 100 Hell runs.
Insanely addictive, deceptively deep and so well balanced.
It deserves every praise it gets. Afterwards, I tried many other platformers but none captured my attention to even finish them once, let alone dethrone Spelunky.