The fight obviously is pretty difficult on its own and pretty much everything needs to go right in order for you to win. However, in addition enemies can used ranged weapons to shoot through physical surfaces such as the grated floor above the arena and the high ground stone floor around the arena. I parked Gale on the metal grate above the floor in order to rain down fire and I keep getting knocked off despite the enemies not having an uninterrupted path to hit me. Additionally, they will park themselves directly underneath my other characters on high ground and shoot through the ceiling in order to hit me. The numerous ranged attackers do not seem to be suffering penalties from low ground either.
Last but not least every once in awhile the Gnomes will start off the battle hostile for no apparent reason.
