The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Wisse Keizer:
MC is for Multiplayer Collection. The Multiplayer Collection consists of a selection of games that can be played by MULTIPLE players on a SINGLE device. The Multiplayer Collection currently holds Tic Tac Toe and Connect Four. Up next are Chess and Checkers. All Multiplayer Collection games are available for FREE on the app store. MC Master, however, unites ALL of the Multiplayer Collection games in a SINGLE app. It is always the FIRST to receive updates, and when a new game is added to the Multiplayer Collection, it will be available in MC Master even before it appears in the App Store.