Currenlty the portal tag is applied to both games about Portal the game and Minecraft portals.
One (or both) need changing to disambiguate.
There was only one instance of the Minecraft version, which I have consequently removed.
As well, to describe plain portals is... not the best of tasks. It's about as useful as door, which I'm aware exists but I'm sure many don't think it's all that necessary. It lacks the amount of universal, game-level applicability that I think is required to be a useful semi-dependent tag.