Alright. I'm not sure what I can help you with, but I'm going to list what I seems off to me.
Why is his past self apologizing for the weapons? This implies several things that don't make sense: 1) The protagonist doesn't like the weapons, which counters him using them to rid the city of corruption; 2) The protagonist has foreseen his own amnesia, which is illogical; and 3) The protagonist is emotionless. Now, 1 and 3 aren't necessarily flaws, since they can be justified from the head trauma, but then what caused his head trauma? Do we, the readers, ever find out, or will it remain a mystery?
Why is he the hero? If his purpose is simply to clean up crime, then are we supposed to find ourselves rooting for him? Or is his efforts to clean up the city causing more harm and fear than good? I mean, he finds a convenient stash of weapons and decides to do good with them. It's a logical choice. Some might refuse. But why does he hate corruption? Everyone has a reason to fight crime, from vengeance to money to fame to because they felt like it one day. Does the corruption stop him from his goals? Is the corruption a stain on humanity? There is always a reason behind actions, and the reasoning is what connects or disconnects us from characters.
Basically, what am I supposed to feel while reading it? Right now, it feels like Batman went and actually started killing people. And that, quite frankly, would be a terrifying thought. How does he know these people are criminals? Did he watch the crime? Did they kill someone in front of the protagonist? If they did, could he have prevented it, or is he only out to find and kill criminals? If they didn't, who's saying they committed any crime? Think of how simple it would be to send a vigilante to kill an innocent person. And an emotionless one at that.
And that's all I can think of for now. I don't mean to confuse or badger you about any points at all, but what you should be asking yourself is why would this happen? The answer only has to make sense in the story. Like, why did he get a concussion? Why does he have these weapons? Your characters don't necessarily have to know why, but if you do, you can justify your characters' actions better.
And so ends my ranting. Sorry that it's fairly unorganized.