Project: Paper2D

For strictly 2D or isometric games you should definitely look at Godot Engine, extremely lightweight.

I’ve personally tried it myself and build a small level similar to what has done for his platformer game here, except that it only took me few hours including some art.

EPIC could build a 2D engine alongside UE4 for 2D games. By faking 2D in a 3D environment is not smart.