2D Boy's highly innovative World of Goo will contain an online co-op mode exclusive to the WiiWare version.

We've seen so many great and wonderful games announced for WiiWare which are armed with an array of great features such as downloadable content, online leaderboards and Wi-Fi multiplayer that it's surprising that a lot of developers think it's difficult to do this for retail games.

2D Boy have just announced a new feature to make their physics-based World of Goo sound even more appealing than it already was. The title will feature an online two-player co-op mode exclusive to the WiiWare edition of the game, giving this version a 1-Up over the PC, Mac and Linux versions. It's still unconfirmed as to whether the online World of Goo Corporation minigame (where players worldwide compete to make the tallest goo tower out of goos collected in single-player) will be included in the WiiWare version, however.

World of Goo is scheduled to hit WiiWare this summer. Click here to read our hands-on preview of this rather excellent physics-puzzler.