Last week I played the first 30 minutes of ABZU and absolutely adored it. As I progressed into the second hour of the game (it runs about 1.5 hours in length total) the game moves from a very freeform journey through the ocean to something much more. Although it still doesn’t feature any narration or dialog, you begin to piece together a story from the different rooms you travel through on your way to a rather climatic ending.
I’ll be honest, you really should buy this game and play it yourself. It’s beautiful and graceful and controls in a way that makes me feel like I’ve actually been underwater for hours. But if instead you’d prefer watching a truly cinematic experience, go check out this playlist on YouTube and watch the full game. I highly recommend a dark room and headphones.