This might sound crazy for a game called 5-Minute Dungeon but would you consider changing the app slightly to add difficulty, where easy might take ~10 minutes or so, normal is 5 and hard can be ~4 minutes (or something along those lines)

While the 5 minutes is great for adults, I did use around 8-10 minutes when I played this game with my niece and nephew, which they loved, but we were never able to do it in 5.

Not a big deal if it won't happen as we can always keep using the regular phone timer when kids are playing to change the time, but I figure this might be an easy enough change to make it easier to play for even more people.

And instant back for me for such a great and quick game :)