I don't think it will be able to make a comeback. Being able to get out 4 energies in 1 turn only gets you at what, 100 damage? Fighting types are heavy in the meta right now which puts Darkrai at a huge disadvantage.
Also, your scenario turn one depends on whether or not you have multiple energies in your hand. If you start Darkrai EX, you would have to have 3 energies and Prism Star Dakrai along with at least 1 max elixir to pull this off. That's 6 cards out of the 8 (draw 1 after turn starts) you will have to have in order to achieve this, which is unlikely. If you play against a buzzwole, all they would need is 1 strong energy, choice band and Regirock EX (30 + 20 + 30 + 10 = 90 x 2 = 180) to knock you out. That's 4 out of 8 cards in their hand which is not unlikely. Plus they run Brooklet hill which allows them to search for Regirock so that makes it more likely that they can take you out!
Maybe you can play around with Darkrai GX as well in order to accelerate more energy at once. The issue is that the deck would require you to have energy all over the place in order for you to attach it efficienctly. 4 darkrai GX can let you attach 4 energies a turn if you get darkrai and an energy in your discard pile (This is highly unlikely to happen all at once). You can run something like 3 Darkrai EX, 4 Darkrai GX and a Prism Star Darkrai and see how that goes for you.
