When it was first released, the Microsoft Entertainment Pack was not conceived of as being the first in a series and so was not actually known by the number 1. In fact the Microsoft Entertainment Pack box cover, shown on the left, was designed to closely match the Windows 3.0 box cover. As you can see, the big selling point for this package was a Windows version of the very popular Tetris game.
Once Microsoft recognized the popularity of the Microsoft Entertainment Pack, a second version was conceived and the original was repackaged as Microsoft Entertainment Pack 1, as you can see from the box cover on the right.
Image created by Greg Shultz for TechRepublic, all rights reserved.