Or, perhaps it was the sweet spot. A few years earlier a 7up advert was the game¹, although to be fair it isn't that bad for a 90s platformer.
You cant hear about it from David himself in this podcast: "The Making of Earthworm Jim with David Perry - The Retro Hour EP319" https://www.youtube.com/watch?v=UzETRBuzfWY
part about advert gaming is at https://youtu.be/UzETRBuzfWY?t=3820