[JonathonW]

Looks like they have part of what made Doom unique (at the time)-- they've got height differences and non-perpendicular walls, but don't quite have the same lighting and texture mapping capability that Doom had.

And the demo doesn't show whether or not they have Doom's dynamic capabilities (that let level builders make things like moving elevators).

This looks like it's probably somewhere between Wolfenstein 3D and Doom in terms of engine features.