The GOG version has broken controller support, and only a few old controllers work. The Steam version uses the Steam controller handling system so that works fine as long as Steam is running. I only want to support DRM-free games though, but until GOG or the developer fix this issue, I'll just be giving the GOG version two stars. Now that this game has split-screen co-op, it needs polished controller support now more than ever! If this issue gets resolved, I'll be updating this review, but as of SV 1.5.1 this hasn't been fixed. Otherwise, this is a great game!
