Update on
Shapeshifter findings (both the card and the enemy):
The AI cast
Shapeshifter correctly in a later duel, so the problem may not be related to that card.
In the blue castle, I duelled another
Shapeshifter who received
Serendib Efreet as starting advantage. When she had two Islands out, she cast another
Serendib Efreet, even though it is not in her deck, and she did it for free (both islands remained untapped). So
Clone or
Vesuvan Doppelganger (which are both in her deck) may be involved somehow, but how can she try to cast them when she doesn't have enough mana? Weird.
Nether Shadow does not return from the grave. This was a problem in early versions of Shandalar but IIRC it works fine in the 2012 download. Or maybe I am confusing it with a modern Manalink version?
See the screenshot of the AI's graveyard here:
http://i103.photobucket.com/albums/m156/jiansonz/Nether%20trobles_zpsq7cbmni3.jpgClearly enough creature cards above the shadows.
The game does not let me counter an Artifact Creature spell with
False Summoning. I am unsure about the rules here (if it's supposed to work against Artifact Creatures or not), though.
EDIT: Another thing: the game frequently freezes when I duel against a Paladin. My guess is that
Sleight of Mind is the culprit, because it happens in situations where that spell could be cast in a useful way.
I noticed an AI problem with the Paladin also. It often plays a
Tundra as its first move (which is good) but then I´ve seen it (later in the duel)
Magical Hack the
Tundra so it counts as a
Plains and as a
Mountain (produces W or R), often cutting off its only access to blue mana. This didn't happen in classic Shandalar. (although this was on Sorcerer difficulty - I have otherwise not played anything other than Wizard difficulty for years)