That's normal in SG, Steam API, can't handle these "edition" titles.

Thanks for the heads-up!

Yes

The actual Two Horned Helmet Edition is actually DLC from what I can see. It's like an upgrade that include a season pass. I'm guessing that's why you can't enter for it.
https://store.steampowered.com/app/394340/Valhalla_Hills_TwoHorned_Helmet_Edition/

I did want to mention I own the base game but nothing else and the bundle price is showing $1.29 for me which isn't technically correct going by how it's displaying the price for me. The two DLCs that have a price are for $0.49 each and the Two Horned Helmet upgrade is N/A. So the Two Horned Helmet upgrade even though it has no price as it's marked N/A is the rest of the price.

This is what's included with the Two Horned Edition
• Season Pass including 2 DLCs
• 5 Special Ingame Items
• Digital Artbook
• Wallpaper
• Digital Soundtrack
• Developer Video