It's a bizarre game in many regards, so it makes sense. I don't think McDonald's has even referenced its old mascots in the last 15 years before this Grimace Birthday thing.
But 20 years+ ago? This would have been a dime a dozen licensed game.
I actually thought the game was pretty ok overall. It's not a masterpiece or anything, but I did play all the way through it, and I had fun the entire time. Certainly better than I thought a freeware promotion game would be.