You have two problems with this hand. First, you have middle pair. If he has a K, you may have some problems. If an A comes, you may have the winning hand, assuming he didn't call with AK. Second, you are out of position. Betting may help define your hand, but it could also cost you a lot of chips.
You check. Villain bets 200 and you call.
Turn is
You check and villain checks. What does this mean?
River is a blank, no help to either hand, you think. You check, and villain bets 400.
What do you do?
"Are the players better as the stakes go up? It's not an exam; it's a buyin." Barry Tanenbaum