The demo for BC2 is actually an Xbox 360 exclusive. Luckily I have one, and it's actually a multiplayer demo at that which is becoming less and less rare now a days.
As for Valkyria Chronicles, well, it's really a strategy game. Not like how Brutal Legend had a hidden agenda with their RTS, but like full on turn based strategy. All of the "roleplaying" aspects come in the form of you recruiting, upgrading, and training your squad in between battles. The sad part about that is it's all done via horrific menus with absolutely no character control. U just read a brief description about a soldier (laughable ones), then put them in your squad or don't.
Check out this hilarious review of it from one of my favorite cynical reviewers:
The Escapist : Video Galleries : Zero Punctuation : Valkyria Chronicles