I found some bugs:
1. card Weakness (1 black mana cost) - If opponent plays it, it taps your creature. But you can't untap it during your upkeep phase, by paying 4 mana.
2. card Skullclamp (1 mana cost, artifact) - This one actually makes this card even better... It says on the card: "When equipped creature is put into a graveyard, draw 2 cards." If you unsommon equiped creature, or it gets unsommoned by your opponent, you also draw 2 cards!!! (This card then makes a killer combo with Esperzoa, and for example Ornithopter)

3. cards Swords Of Light and Shadow, Swords of Fire and Ice (both 3 mana cost, artifact-Equpment) - If they are equipped together, after an succsesful attack, you cant assign 2 damage from Sword of Fire and Ice, because your graveyard is still open from the effect of "returning creature card from graveyard" from card Swords of Light and Shadow.
4. card Max Pearl (0 mana cost, artifact) - you can play it without discarding a land card (if you dont have land in Ur hand) its not activated though. But you can activate it by playing another Max Pearl and discarding a land. Then you have 2 Max Pearls (or more) for 1 land.
P.S. I know this are minor issuses. But hey, I thought you might appriciate this report. Since you strike me as an great enthusiasts of this card game. I know I am. ; )
Thanks again for this great game.