I think that if you call pre-flop out of position with ace-rag, you have to be willing to put some chips into the pot with ace high if you miss, otherwise what's the point of calling when you'll miss the flop most of the time. Hand 19 for example, that flop probably missed him too in which case you probably have the best hand. I'd call that bet and I might call another bet on the turn depending on the card. If you're not willing to do that then fold pre-flop.

In a heads-up match the more aggressive player wins more often than not so you should NEVER check-call the flop with something like a baby flush draw or a gutshot. The way you played the flop on Hand 33 and Hand 37 is bad, if you want to put more money in the pot then you should be the guy betting out on the flop instead of checking and calling. It's OK to check-call the flop if you have a pair and you know your opponent is betting with nothing a lot of the time when you check to him, but don't do this with a crappy drawing hand.

Hand 45 - really confused why you called the river with ten high, even if he's bluffing he's probably beating you.

Also, when one of the players has less than 10 big blinds left you're pretty much playing preflop allin-or-fold poker which means you shouldn't be limping in from the small blind with garbage hands like 52 suited. This is OK when you both have bigger stacks though. You should never make a small raise and fold to an all-in like you did in Hand 53, when one of you is that short. You'd be surprised how easily you can dominate a heads-up match against a lot of bad players who fold every time when you go all-in every time and then when they finally call, sometimes you win anyway and even if you don't, they're usually so short by then that you can resume dominating them after you double them up.