It might be an interesting variation for some but I (and almost everyone in this community) identify a dungeon crawler as something that is played on a regular (2D) grid in first person. The line in the sand has been drawn there since that's what we grew up with and are used to. All other aspects are open for interpretation and innovation, but "first person", "grid based" and "90 degree turns" are not.
Way I'd see it, it 'might' be fudgeable at a push, under a big solid "maybe?" But a quick calculator mess made me think of how a "hex" Tile game would in fact, feature 60 degree turns, even if it allowed for a 180 degree 'back switch'.
The second thing to be mindful on, is even if you 'could' do it. Should you do it, is another matter. When one has to think of the KISS Principle when it comes to any game design. Especially towards Game Jams.
Still, if it's under a "first person, 2D" Perspective, it might lead to a unique visual take on being able to see in 'five' directions, up-to wise. But that's just a hazard guess, without doing a 'dummy' rig to see how walls would look like on a 2D Plane at a glance, if placed on a 'hexagonal' format, instead of the iconic square format which is part of this game jam, I'd presume.
