I was able to accomplish the task, though I didn't get the silver shape.
Some notes:
* This was not the first time I went through the dungeon. (I think it might have been fair to allow referring to a map before entering the dungeon, but not once the dungeon has been entered, to simulate past knowledge, but I didn't do that here.)
* I did use save states. This particular dungeon has some nasty trolls, including one-way paths back to the start and even a (anti?)softlock at one point. (I also wanted to see said softlock.)
* It's a good thing I remembered the Sinister puzzle, as that can be quite nasty. (For anyone not familiar with this, there's a riddle in a small room in a large dark room that you need to answer in order to make a door appear in the next dark zone, which is a maze.)
* I did accept being sent backwards in the dungeon at one point, mainly because I got into a fight and got some good treasure out of it.
(As a side note, I'm seeing some similarities between the design of later parts of Bard's Tale and that of Mario troll levels; we see being sent back, the (anti?)softlock I mentioned, and even a teleporter that takes you to a place that looks identical that you may run into when trying to avoid a spinner.)
(Note that I do *not* recommend attempting this on your first playthrough.)