@desolutionist I know, I know, but I don't think there's any energy card that's played right now in Vintage, so I'd ignore energy when evaluating the card and consider those just like a "Extra turn counter" on Aether Heart itself. Sure, if Dynavolt Tower or Aetherworks Marvel or Deadlock Trap or Glimmer of Genius see play, then I'll change my way of thinking about the card.
Please consider making a thread for the new black removal spell and deleting this one. There's no way in holy hell that this card is playable. The one scenario mentioned with paradoxical outcome is a scenario where you'd ACTUALLY WIN if you played tendrils or mentor instead.of taking an extra turn or two. If you're into extra turn combos word is there's a card from alpha for that...
Usually I don't post snarky comments in threads like this, but this card just really, really seems bad to me. I mean, yeah, it'll possibly do something in standard or modern , but it's just not where you want to be.
Time Vault is better, easier, and not nearly as prevalent as it once was.
If you're playing Mentor or Pyromancer a time walk effect is amazing. However it's much more efficient to go Walk, snap/JVP/YWill, replay Walk, win, than do anything with this monstrosity.