Neat slideshow. Would have been cool to allow players to actually play a bit of pong before going down the rabbit hole.
Controls were weird. The "proceed" key doesn't make sense at all considering that the players will be in pong mode when they start. Pressing right on the keyboard is like the last thing one would try in a pong game. Also allowing the player to "go back" made it feel even more like just a slideshow. You should have disabled the next/back functionality when prompting the user, currently you can pretty much completely break the game.
The bubble animations looked quite nice. One "annoying" thing on it was that hand/bubble overlay issue when fading their alpha. Can't instantly come up with how to fix it easily though (without doing a custom shader). I usually just shy away from adding alpha fades to such composite elements. Also, quite a lot of the texts didn't fit the bubbles properly.