Warframe: Ninjas play free.
The game is much improved from its initial beginnings -- and playing it on the X1X in dynamic 4K (not true/native 4K) it looks razor-sharp and moves smoothly with no discernable slowdown so far (tho' I am admittedly still in the early levels).
Free-to-Play. You spend money to buy materials to build your gear (which you can also grind for) -- but this game is all about The Grind. You will end up replaying the same missions AND those missions are largely simple and involve killing wave after wave of baddies in variations. Combat is king, hell MOVEMENT IS KING.
3rd-person PvE adventure play. Mission-based with only one open world section. Maps are randomly generated from a set list of parts so there is at least some replay variety. Strikes & Horde modes, no Destiny-like Raiding. PvP is largely secondary.
Warframe's artwork is incredible. Absolutely looks otherworldly & celestial.
I didn't give this game a second look when it was first release but now? This game is p o l i s h e d -- you might not like the action but the visuals are sumptuous. I'm looking forward to diving deep.