Stuff that had bugs for me:
Casting
Fire//Ice (Fire version) does nothing. It asked me if I wanted to play Fire or Ice, and I chose Fire, and it just went to the graveyard after I tapped 1R. I'll edit once I get it again and cast Ice. (edit, got this card again and it properly killed an
Onulet with Fire version, so I dunno what's going on) (edit again) Ice version works, and it automatically chose Ice when no red mana was available, which is nice.
Bringer of the Blue Dawn asks to draw 2 cards when it does combat damage. Fortunately, I can select cancel, but the AI could abuse it. The upkeep draw works normally. (It was equipped with
Loxodon Warhammer. The next turn, I unequipped it, attacked with Bringer, and killed opponent, and it didn't ask me to draw 2 cards on the kill)
When blocking with a creature with
Loxodon Warhammer (different game) I took lethal damage from the unblocked attackers, and before the
Lifelink processed to save me, the game was over, which is in keeping with modern rules but is a violation of the 4th edition days which this engine is based on.
Temple of the False God will give 2 mana even with less lands (in this case, 3 was enough)
(very minor)
Bringer of the Green Dawn's beast tokens have the goblin token picture from
Dragon Fodder. He seems to work properly otherwise, including dealing combat damage to the player.
After attacking with
Maelstrom Archangel, I was attacked back by an
Azure Drake on AI's turn, and was asked upon being damaged to play a card for free.
Archangel worked correctly on my attack phase.
After dealing damage to opponent with Honden of Infinite, I was asked to use
Sword of Fire and Ice, so that seems to be processing every time damage is dealt, regardless of the source or the target. I think the Honden is fine, though. The black, blue, and white ones work; I have not yet drawn the green one.
Similar to
Archangel, I attacked with Tarmogyf which had a
Sword of Fire and Ice on it. It worked normally on my turn, but when I got hit by unblocked creatures the next turn, it processed again. The next turn, when I had a wall, I blocked an attacker, and Sword processed again. (tarmogyf with sword was tapped from attacking again,
Wall of Reverence blocked
Kird Ape, nothing died; dunno why it even attacked :p)
When Maelstrom Angel put
Bringer of the Black Dawn into play, I was asked to pay BUWGR, but I could cancel it with no ill effect. (ditto with
Eureka putting Bringers into play
AI is not attacking with
Goblins of the Flarg when I have
Blood Crypt (part mountain) in play. This might not be a bug, but given the board situation, it is extremely unusual, since AI does not hesitate to attack with unblockable creatures, even when doing so allows you to kill it next turn with your attackers. edit: confirmed that
Blood Crypt doesn't work with mountainwalk. Next turn I played
Volcanic Island. AI immediately attacked, then strip mined my volcanic
Island during the attacker fast effect phase, and I am now allowed to block.
A Fetchland no longer produced mana for no reason when tapped while
Mana Flare was in play. edit: oops, looks like I spoke too soon. It just did this time. But, it is counterbalanced by the fact that when sacrificing
Sulfur Vent for RU, I did not get one more mana from
Mana Flare, hehe. I've no idea why it should give mana to the land that shouldn't get it, and deny mana to the land that should.
Stuff that works for me:
Aether Vial (though it only lasted 3 turns before it got Disenchanted). It tells you how many counters it has during upkeep and asks for a choice, and correctly let me play a cost 2 creature when it had 2 counters.
Electrolyze now has a dialogue box
Eureka seems to be fine, I played 5 cards with it. AI didn't play any cards, though, but he had only 2 in hand and one turned out to be
Disenchant he used on one I played with
Eureka after it finished resolving, so I'm not sure yet if AI will play things.
Bringer of the _ Dawn (black blue and green) all seem to work fine.
Hondens (white one and black one) worked, both individually and together. Red one and blue ones work, haven't had them interact with other hondens yet. Haven't drawn the green one yet.
Wall of Reverence works fine. (and is probably one of the best walls I've ever seen, aside from
Wall of Blossoms or a few like that)
Overgrown Tomb played correctly when
Living Lands was in play.
Twice now, when using
Academy Rector's dying ability, when I refused to cheat and search for a 2nd enchantment, a card (seemingly at random) in play was buried. Once it was
Survival of the Fittest, the other time it was
Ravenous Rats.
Stuff that is somewhat annoying, but still works:
Wasteland and the
Tinder Farm lands (the ones I've had in play so far anyway from those saclands) ask me every time whether I want mana or to sac them when I doubleclick a card to play it, having computer tap my lands. There is also no cancel, like strip mine or library of Alexandria, if I don't want to tap that land. The saclands don't consider their sacrificial mana when it comes to what you can cast in hand, but that's a good thing in my opinion, the same way it won't consider a dark ritual or other cards like that until you actually use it for mana.
Academy Rector seems to lag the game badly every time it is in combat, but other than the already known issues, I haven't seen anything.
Browbeat works fine, but I guess I'm retarded because I couldn't figure out what the first menu was for, and didn't realize that browbeat lets the caster take 5 damage, so I smoked myself in the head for 5 damage and did nothing to my opponent :p The second time around, I said 'no thanks' on beaning myself for 5, and AI chose to take 5 damage. So I guess the menu's wording might need better wording, or I need to stop being retarded

edit: apparently the AI is just as retarded as I am, at least that last time. I just did this again, and the AI ended up getting the cards. The way the menus work and the extremely odd wording of this card make it not obvious at all. I think the real life card simply gave opponent a choice between taking 5 or allowing you to draw 3 cards, and did not require all this, which is why I'm messing up in play with it here.
AI errors:
AI does not want to attack with
Platinum Angel (life totals 17 to 16, no other creatures in play, I have nothing but land) After waiting several turns, he then dropped me to 7 with fireball/lightning bolt on one turn and then attacked, with no change in my board.
AI played
Coat of Arms after attackers phase (while sitting on seven bitterblossom faeries!) and I had only two fliers in defense. Next turn, of course, I died... painfully. Probably there is one bit you can change somewhere, since AI knows to play
Goblin King,
Lord of Atlantis, and newer cards that give bonuses to other creatures first. (though it doesn't know to play all creatures first when it has creatures like
Keldon Warlord in play)
Stuff that is REALLY cool:
Yawgmoth's Bargain and
Eureka
