The main advantage I'd expect Portal to have over other games is the spatial memory required to remember where you've already put your portals, while they're no

The main advantage I'd expect Portal to have over other games is the spatial memory required to remember where you've already put your portals, while they're not currently on the screen. I expect that a linear game would score the lowest, since there's no incentive to build a mental model of the map inside your head. Games with sprawling levels that encourage backtracking would be somewhere in between, but those are kind of frustrating and outdated these days, and you can still complete them by randomly walking around until you reach your next goal. Portal games have backtracking, but you need to intentionally place a portal in both locations, which you can't do accidentally.