id like to see a bet on the flop. The 0.40 bet on the turn is a fold or raise situation, personally i would re-raise the 0.40, without the ace he cant call, so at least you get the information. If he has AK you would expect him to lead at the pot hoping to trap someone with Ax, his check on the flop shows weakness as does his turn bet, re-raise him, if he calls then the hand is over.