Oh man oh man oh man this is a spectacularly good concept and I really want to see this in game. I could do without the weird achievement unlock-style purchase condition, but it's easily the best card concept I've seen pitched in a while.
Balance-wise, I think you pegged it pretty well. If anything I'd say it's underpowered--one primary use here is as a cheap imitation Silence, and getting double the duration for double the cost is a really good trade, but while you can use Distortion as a specific counter to certain spells you're generally not going to be able to completely lock down the opponent since they can still play creatures/permanents. They also get the option to spend their spells as Shockwaves for free CC capability, which tends to make for a more interesting gameplay experience than being stuck not able to do anything at all. I would say it could use -1 to the cost or possibly +1 duration.
The uses for this card would be amazing, though, and would fill a niche that people have been badly wanting for a while. It has some interesting possibilities for deckbuilding flexibility, since you can essentially add dual-use CC to all the spell cards in your deck, but more importantly
it's a soft counter to a lot of control/denial cards. Explosion, Steal, Black Hole, Quicksand, Silence, Nightmare--a lot of the most frustrating cards in the game can be held off while you have Distortion up, plus it can stop some potent setup cards such as Supernova or Quintessence. At the same time, though, it doesn't threaten to trivialize any of these strategies: the cost per turn on this is a significant drag, low duration means it takes a lot of cards to chain them, and you're feeding your opponent free CC power.
The
works really well, too. I think
badly needs more love, and the gameplay themes of flexibility and freedom (in that it can counter denial strategies) are a great thematic fit.
