Steam game won't delete

I bought a game from Steam that I've since then returned and uninstalled on my Macbook Pro. Despite that, the game still takes up 6,24 GB of my storage.

The game only shows up on when I look at what programs take up the most storage - when I search for it on Finder or any other places on my Mac, the game doesn't come up.

I've tried deleting the game from the storage menu, but nothing happens: It simply doesn't react. Other applications delete just fine, except this one.

Another strange thing I've noticed, is that it says the game was "Never opened". Here's a screenshot of how it looks: (It's in danish)

Does anyone know how I can get rid of this game once and for all? It's really frustrating that it won't delete.