Have you any flying foes, or some that can teleport on short distances, like in within a room.
Not yet. I can't think how to incorporate that into what we already have. There's no concept of position or range in the game. You're in an encounter or you're not. Come to think of it, we do have flying foes – bats – but that doesn't mean anything as far as the game is concerned, except maybe +1 Defense.
To me, the monsters that were the most challenging (annoying but so satisfing to kill <img src="/ubbthreads/images/graemlins/delight.gif" alt="" />) were always those that regenerate themselves. Like those trolls in Icewind Dale that you can't kill except with a fire/acid enchanted weapon or when they're quite dead they get inert and wake up full health again after a little while...
That's a good idea! We can have a monster that heals 1 Damage each turn. Kill it quickly! Any other ideas we can build off that?