Bugs

Bugs that can be fixed:
-Kobold Lords Pump themselves
-Pearl Dragon has wrong pump cost
-Kami is the Cresent Moon doesn't work when tapped, and isn't Legendary
-2 images listed for Voltaic Key, even though there is only 1
-Pump knights use colorless mana to pump
-Spirit of the knight always has first strike
-List other approximations here

Bugs that can maybe be fixed, but require some new coder skills:
-Goldmeadow Stalwart / Wren's Run Vanquisher / Silvergill Adept do not need a reveal to play cheaply
-Merrow Reejery is missing 2ndary ability
-Cloudgoat Ranger is missing 2ndary ability
-Brainstorm doesn't let you put every type of card back into your deck

Bugs that cannot be fixed (engine limitations):
-Tooth and Nail Entwine doesn't let you play cards from your hand, only your deck
-Hybrid doesn't work
-AI can cheat when using comes into play abilities and not choose a target
-Comes into play doens't use the stack
-Colored Artifacts show as castable even when they are not
-Fetchlands / terramorphic expanse freeze the game for some versions
-CMC is wrong for add-on costs like Buyback, Entwine, etc

Unconfirmed Bugs
-Tribal Flames doesn't work