I remember the main noticeable difference being ray traced reflections. However that was mostly on immovable objects in extremely simple scenes (office building). Old techniques could've gotten 90% there using cubemaps, screen space reflections, and/or rasterized overlays for dynamic objects like player characters. Or maybe just completely rasterize them, since the scenes are so simple and everything is flat surfaces with right angles anyways. Might've looked better even because you don't get issues with shaders written for a rasterized world on objects that are reflected.
Games that heavily advertise raytracing typically don't use traditional techniques properly at all, making it seem like a bigger graphical jump than it really is. You're not comparing to a real baseline.
Overall that was pretty much the poorest way to advertise the new tech. It's much more impressive in situations where traditional techniques struggle (such as reflections in situations with no right angles or irregular surfaces).
The "office building" setting meant resticted areas, sure, but it features TONS of reflections - especially transparent reflections (which are practically impossible to decently approximate with screen space techniques).
Oh, and: The Northlight Engine already did more than most other engines at the time to get "90% there" with a ton of hybrid techniques, not least being one of the pioneers regarding realtime software GI.