Snake and dragon boat in blue are definitely 3D – you can see an aspect change on the head of the dragon boat and the snake just… well, has volume, that we get to see different sides of.
The sword slash to the neck (brown section right after the boat) is also 3D as there is an aspect change on the hand and we get to see both sides of the hand – you also get to see more of his eye area inside the helmet. While some of this could easily be 2D with Duik or similar (or more likely with their own software – it is a software company after all) its probably a mix of both. I would agree that doing some of that “sketchy look” stuff in 3D would be simpler in 2D due to intentionally ratty edges but some of the forced perspective stuff on limbs is easier in 3D – doable in 2D? For sure! But why bother if you have the assets – which they probably do from the game.
The background people have all the hallmarks in the animation style of 2d puppet tool stuff.
Many of these companies use custom software that can combine 2D and 3D so you get the best of both worlds without the render hit of doing 2D in a 3D package.
AE is 2D only. Yes you can fake 3D with angled 3D planes and you can set these flat planes in what feels like 3D, and you can use something like Element 3D to get true 3D, but as amazing as Element is, doing true 3D is easier in a package dedicated for it. Heck, even Particular isn’t truly 3D (at least by the time the objects show up in the comp window)
That’s not to say you shouldn’t try in AE. We just finished one in fact.
You can also extend Ae with C4D – the combo of Ae and C4d now is pretty cool. You can bring one into the other to get the benefits of both and keep everything “live”.
There is no one way of doing things. While its cool to be able to say “that’s actually all 2D” and have people be amazed for a day or two, there will be someone else who produces something that looks just as good, but did it in half the time for less money and has the rest of the day off because he did it in either 3D or a combo of 2D and 3D.
There’s a plug in for AE now for offset layers to give the illusion of depth – stacking – you can even do faces turning – I forget what its called. I don’t think the shield is a that, I think its 3D. But you could do it with a 3D plane and a curved top matte on a separate layer. The plane rotates into view and the curved matte tracks with the arm to keep the correct curve for the shield face. You can also warp surfaces as they turn to reduce what looks like an edge profile.
If it makes sense to use one or the other go for it. But in the end, the client doesn’t care how it was done. Most of this is a mix with the 3D stuff having textures that are hand-drawn so it looks 2Dish. Or it could be all 3D to keep things simple in one package, using some 3D objects and some just as flats.