Highly doubtful. The point of this kind of software is to appeal to non-game devs. People who can't code nor do graphic design. If it had a full blown scripting system it probably would be too complicated for their target audience, something Game Builder Garage suffered from even though they went to great lengths to simplify it, but most people can't think like a programmer. Sounds like you need to download Game Maker and create a zelda-like yourself.
Haha, even GBG was quite limited for what it was. After all, it was presented as a game that teaches the basics of actual programming, only to lack some very basic functions any game engine should have while still being needlessly complex in some aspects. Works nice as puzzle game though.
To be clear, I don't expect unlimited possibilities in a simple dungeon maker. I chose some very common and simple elements among those that made Zelda and similar games so great, knowing that the implementation is not quite as simple, to illustrate a point.
My point is that when you sell a regular UGC exchange game with fairly tight limitations that allow varied but ultimately generic creations, advertising it with "unlimited creativity" is a lie.
There would be a plethora of slogans that are at least technically true, like "Countless Possibilities" (at least until some math geek calculates the permutations) or "Build YOUR Dungeon" (although not necessarily the exact dungeon you want), but "unlimited" is just plain false.