The first Microsoft Entertainment Pack for Windows didn’t have a number after its name because it was the first one, and nobody knew that there were going to be any sequels.¹

It may not have had a big number 1 on the box, but initial runs did have a bright red sticker that said, “Now includes TETRIS for Windows!” There was no mention of Tetris anywhere else on the box. Why did it announce the inclusion of Tetris only with a sticker?

Because at the time the first run of boxes were being printed, the negotiations to license Tetris hadn’t yet concluded. There was a chance that the negotiations would fall through, and the Entertainment Pack would have to be released without Tetris.

Rather than including Tetris on the box art and risking having to destroy a production run of boxes if the license couldn’t be acquired in time, the decision was made to produce boxes that omitted any screen shots or even a mention of Tetris. In anticipation of the deal coming to a satisfactory conclusion, they did have a run of red stickers on standby. When the deal was completed, the “Now includes TETRIS for Windows!” stickers were applied to the already-made boxes.

Later runs of the product box incorporated the Tetris sticker into the box art, and even called itself “Microsoft Entertainment Pack 1” and suggested that you try out “other volumes of Microsoft Entertainment Pack for Windows” because packs 2 through 4 had already been released by then.

So I guess that means that if you have a copy of Microsoft Entertainment Pack for Windows with the Tetris sticker, you have an ultra-rare copy, like the original Windows 95 box with a hologram of a shirtless baby.

Bonus chatter: Other sticker shenanigans.

¹ Just like how World War I was initially called “The Great War”. If you had called it “World War I” from the outset, people would look at you funny, like “Do you know something I don’t?”