@Zero, my point with the Reversal was a bit... off, and for some reason I didn't mention Omastar. Play Reversal, Omastar, Gyarados gets sent back to opponent's hand, and then either send the Gyara to the Lost Zone or the Magikarp (whichever seems more advantageous). Omastar gives this deck a boost. All you need to do is do that against 2 Gyaras, and then the Gyara player's going for the 3-shot instead.
Your point on the Seekers is true, but with Omastar, it's not absolutely necessary to use it every turn (plus, the odds aren't that great that your opponent has no 'mon in his hand to begin with, but that's easily checkable with Looker's). Twins helps a whole lot, too, when you're not using Seeker/Lookers, etc., since LostGar doesn't need prizes.