You can play matches of up to 10 minutes long, all taking place in the Konami Stadium. The PC demo of PES 2015 is the same as the console versions.
You can get Steam here, and download the PES PC demo here. Nevertheless, a Steam account is free, and it’s easy to manage your PC games there. In a since deleted news article, Konami said the demo would be available via Steam and ‘traditional direct download’, but so far only the former is true. It was delayed, and there’s still no direct download available from Konami as promised, but PC gamers can now get the PES 2015 demo that console owners have been enjoying for the last month.