People have too little faith in 2.5D it seems. Or some people do.
Frankly I'm certain 2.5D is the best way to go. The model I'm thinking of is MK9; if one takes a moment to look at the backgrounds of the stages in that game, it has very respectable levels of detail, and 3D environments can be used to create far more atmospheric lighting effects and such.
I'm fairly sure if 2.5D is used correctly, and nothing is overlooked, the end result will be appropriately stunning.
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