Not necessarily, depending on what you mean with 3D (although one of the other comments definitely proved it).
If you mean "uses WebGL to render 3D polygons", then there are other possible solutions, like the isometric approach I mentioned before. Given that the developer wants to target linux terminals[0] he is likely to come up with his own rendering scheme, probably not unlike the old software 3D engines of the late eighties/early nineties (like the aforementioned Zarch, or later Bullfrog games like Powermonger and Syndicate 2)
