The gameplay I've seen makes it look like a post filter and tweaking of animations. Basically palletise colours and sample animations at 10 fps or somesuch. Quite a nice idea for a look from a 3D source, although getting convincing sprites should require more work than just reducing the colours.They say it is temporary and a friend told me that they were so lazy they just copied the skeleton king area to recreate most of the world of Diablo 1 and did strange things to animations.
Given I already had to buy the game twice on PS3 because I was sold an unsupported, unpatched version 1 and required to buy the actually-going-to-be-supported version 2 of the same game, I'm loathe to buy it a third time for PS4, especially when the PSN asking price is £60! Especially when I can't resell the PS3 versions. Offer an upgrade price to show you appreciate my custom and loyalty and I might bite again.
It has to be said, that first requirement to buy the game was a pretty shitty move and definitely soured an otherwise incredible game which has provide countless free updates. Us early PS3 buyers who were asked to pay double have a residual bitterness that other D3 players won't appreciate.