Is reachability in fractal mazes with traps EXPTIME complete?
A fractal maze includes one or more copies of itself. For example, see the question Decidability of Fractal Maze or Puzzling StackExchange question Alice and the Fractal Hedge Maze.
In this question, a trap, when stepped on, destroys a maze passage, i.e. if we reach a given vertex (alt. edge), a given edge (if present) is permanently removed from the graph; allowing multiple traps in one location does not change the problem. In a fractal maze, maze copies also copy traps (with trap activation on a per-copy basis). We allow directed edges, but because of traps, that does not matter for the question.
Posted in Q/A format as I was able to answer it while writing out related results, but I welcome other answers, including additional details, tighter bounds, similar questions/variations, and whether computational complexity of fractal mazes has been studied before.
Variations: A restriction is to require the maze to be planar. A strengthening of reachability is to allow reachability infinitely often (this has subtle dynamics), and with a further strengthening requiring the path to be reusable; for these strengthenings, a variation is to disallow directed edges.
Some reachability results
Reachability in undirected graphs is LOGSPACE complete.
Reachability in directed graphs is NL complete; it is open (as of 2022) whether this holds for planar directed graphs.
Reachability in undirected mazes with noncomsumable keys (that open doors) is P complete.
Reachability in mazes with traps, or with consumable keys (I think even if every door works with every key, consuming one key), or with directed paths with nonconsumable keys (or all three) is NP complete.
Reachability in mazes with switches (that toggle some edges) is PSPACE complete.
Reachability in fractal mazes (directed or not) is P complete. To see this, let $C(i,j)$ hold iff exit $i$ is reachable from exit $j$. Then the maze gives a monotonic recursive relation for $C$, and the true $C$ is its least fixed point. (As an aside, taking the greatest fixed point (which is also P complete) corresponds to connectivity when at high enough depth (or in a sense in the limit) we can tunnel through the walls of the submaze.) In the other direction, we can use the reachability to simulate a monotonic circuit. Also, for fractal mazes with $O(\sqrt{\log n})$ (external) exits, reachability is in NL, and LOGSPACE (aka L) for undirected mazes.
Despite being in P, reaching an exit in a fractal maze can take an exponential number of moves, but the maximum depth is polynomial, and the directions can be printed by a (deterministic) PDA having polynomially many internal states.
Reachability in fractal mazes with switches is undecidable, even if the maze directly contains only one copy of itself, each copy directly contains only a single switch, and each switch can be toggled only once. This holds because Turing machines with a single write-once binary tape (i.e. 1→0 is disallowed) are Turing complete as we can repeatedly copy the work area.