It appears as though I am unable to save the game or any options, making it neigh impossible to complete. Where are the local save files supposed to be stored (i'm on Windows 10)? I have tried disabling cloud sync which has no effect.
That's strange, I wonder if it doesn't have access to the folder. Saves are stored under: C:\Users\[USERNAME]\My Documents\SavedGames\Timespinner\Timespinner\AllPlayers\Config.sav
Ah good. That fixes things (it was a permissions issue, as I do some administrative stuff on my machine). It seems like you have a built in "Select new device" prompt that comes up, when it can't be found, but the dialog doesn't actually appear (likely because of a lack of permissions regarding the default directory). A quick fix would be to set the default directory for that prompt's pop up to the base C directory (on Windows at least) so that if there's a permissions issue, then users could fix it themselves by selecting a new directory (that is assuming that you support that, and that this prompt wasn't just legacy code that wasn't meant to make it to the final build).
Yeah, it is legacy code as it's built in XNA. The game is so confused that it can't access the folder, so it begins to behave like an Xbox360 game lol. I'll see if I can make the error messaging better.
This also causes some issues if your Documents folder is redirected to a network location. (Although as a workaround you can map the network location as a drive and redirect the documents folder to that mapped drive, but this is sub-optimal because then windows doesn't think it needs offline sync)