Meet the Snorkels, the friendly aliens from Deneb Gamma IV. One player will control the green Snorkels, and the other player will control the purple Snorkels. Each turn, you place one of your Snorkel pieces on the board. Snorkels never move once they are placed.

Each Snorkel has four breathing tubes coming out of its body. If all of its tubes get blocked by the walls at the edge of the board or by enemy Snorkels, it passes out from lack of air and gets captured by the enemy. The first player to be captured loses the game.

A common practice among Go educators, especially those who work with kids, is to begin by teaching a somewhat simpler variant of Go known as The Capture Game. Snorkels is an adaptation of The capture game by Mark Engelberg, who will donate his share of the proceeds to the American Go Foundation.

http://www.boardgamegeek.com/boardgame/72794/snorkels

Cute. Does it follow Capture Go exactly? In other words, "first to capture wins,"
so there is no ko, throw-in, or snapback?

It follows capture go exactly in the sense you're asking about. However technically it's slightly different in that it starts with the first player, purple, placing a purple piece and then the second player gets to choose whether to swap sides.

See http://www.nestorgames.com/rulebooks/SNORKELS_EN.pdf