EARTH DEFENSE FORCE 6 - About sign in with an Epic Games account. - Steam News
For this game, to enhance cross play and online functionality, Online play requires signing in to your Epic Games account. We apologize for the lack of advance notice. Signing in to your Epic Games account is required the first time you play online. Usuall...
And that's an automatic no buy. Pity, EDF is a very solid franchise otherwise.
It's not an actual EGS requirement, it's a poorly done implementation of the EOS online service. It basically just makes a generic online ID for your steam account, you don't have to actually make an account with email etc or install EGS client. Normally games that use EOS just automatically do that in the background.
Today they've admitted fault and are looking into doing something, likely fix it to use the latter method.
It wasn't malicious like Arrowhead / Sony, just Sandbox being a classic "how to into pc" japanese dev. I'd be outraged over actually forcing an epic account too, but I'll give them the benefit of the doubt on this one.