Originally Posted by
Loony BoB
Really depends on what you mean by deep. There are deep games emotionally, deep games philosophically, deep games politically, deep games lore-wise, deep games in experience or atmosphere, deep games in plot complexity...
"Walking Sims" and Point & Click games tend to be the deepest because they rely 100% on narrative. But 'deep' just sounds so cheesy when describing any particular game, like someone could label Journey as a 'deep' game but there isn't any real narrative at all. On the other hand, you could get a game like Gone Home which could be called deep by some for how it delves into the mind of a character, while others would scoff because they might feel it's just a moody teenage girl's LiveJournal entries.
Games that I would consider to be 'deep' in some kind of sense would include...
Flower
Journey
Gone Home
Firewatch
Deus Ex: Human Revolution (and, I presume, the other games in the series which I have not played)
The Longest Journey/Dreamfall series
The Last of Us
Final Fantasy VII
Lost Odyssey (haven't finished this one but from what I experienced it does very well)