So far I've been having a blast playing on the iPad version of the game, however I find movement a little bit tricky, especially during combat.
Because you have to use your finger to choose where to go or attack, often times I find myself trying to attack someone with my archer, just to accidentally press the tile besides it and I end up just running up at them, effectively killing that character, and potentially my entire group. It is sometimes hard to make sure I am touching the right tile because my finger is covering the tile so I can't see which one is highlighted.
I think that one of two ways to fix this would be nice:
1) Add an undo option just for movement (maybe a one time use per every several turns). I don't see any real way to abuse an undo for movement (at least not anymore than the standard save/reload).
2) Perhaps make it so that if you are already holding one finger on the screen, a second finger's tap will only cause attacks, and not movement.
On a side note, I have not played the original series for Avernum, but I wish that there was some type of explanation for how four people managed to become in the group when the introduction and storyline talk about how you being thrown in Avernum (without references to anyone else).