Microsoft game on Windows makes sense. Microsoft game on PS4 will never happen.

They tell you that you need to sign in to save, but you can sign in to an offline profile. Been that way since the beginning. It's a persistent misconception across the entire internet that you need to be online to save. It was never true.

Bulletstorm saves fine on an offline local profile. Played it on day one that way, never had a problem. All singleplayer GFWL games should be fine, it's the online that's going away.