I've recently played some games as Black that opened like this:
[White "Opponent"] [Black "Me"] [Result "*"] [ECO "B01"] [FEN ""] [CurrentPosition "rnb1kbnr/ppp1pppp/8/3q4/2P5/8/PP1P1PPP/RNBQKBNR b KQkq c3 0 3"] 1.e4 d5 2.exd5 Qxd5 3.c4 *
c4 seems to be a very uncommon move as opposed to Nc3. But it doesn't seem bad at first glance - it allows the knight to go behind the pawn when Nc3 is later played, and grabs some central/queenside space. It also forces the queen to move (although 3.Nc3 would also have done that.)
How do I refute this variation? Or is it perfectly playable?
My opponent and I both have USCF ratings in the 1500s, if that matters.