Fast RMX continues to be one of the most technically accomplished games on the system. But there are other major standouts.
Mario Odyssey I don't think gets anough credit in this area, that game looks excellent. And setting asside the aliasing issues, New Donk is probably the most impressive depiction of a dense urban environment Nintendo has ever produced.
Astral Chain is an interesting one as it does present visually compelling environments but it's actually a lot of tricks going on and mostly makes very, very clever use of Gen 7-era techniques to give the appearance of Gen 8 techniques.
Luigi's Mansion 3 looks excellent with great visuals making use of current gen techniques and exquisite animation.
And then Yoshi's Crafted World is probably one of the best UE4 games on the system in terms of using the tech in a balanced way, despite the resolution issues.
Monolith didn't make as much of a splash in terms of tech with Xenoblade 2 as they did with X - likely due to X having so much excess time in the oven - but there were some definite highlights there that were much more cleanly represented with the improved Torna the Golden Country. I don't think either game is in the "best looking" conversation even with Torna's improvements, but you can tell Monolith is getting there.
For 3rd party, Witcher 3 is the most impressive achievement without a dout, but best looking? For my money, it could be Grid, Dragonball FighterZ, Dragon Quest XI, or Doom.
Edit: Almost forgot Smash Ultimate, which is a huge upgrade over Smash 4.
Last edited by Nuvendil - on 02 December 2019