Some thoughts:
I notice when you attack, you swing the sword twice, does it do twice as much damage as only one swing? Maybe it's best to swing once with each push of the key.
Defense? When I'm jumping onto a small platform with an ogre, they're able to attack me the same amount as I do with them, and they get an extra hit in or two before I land.
I've noticed if I stand further into the ogre, he attacks and does no damage. I was able to stand center mass with an ogre and both of our attacks were not hurting one another.
You might want to think about adding lives. I got fairly far into a level but fell down a hole, then the game restarted from the very beginning; maybe add a continue spot? Also, adding a dash would help with dealing with ogres since there's nothing you can do to defend yourself except to take the damage and hurt them before they hurt you too much. (Where's the replenishment for health in levels?)
I would also like to suggest a reward for killing an ogre. I was able to run past them without getting hurt too much by standing in the middle of them. Maybe if we were rewarded with points that we could spend on upgrades, or some time of item or health came from killing them, it would give more of a sense of achievement or reason to kill them.
Sound FX are pretty minimal here. The sound of the character attacking and music. Maybe add FX for the sword or the mace of the ogres, sounds of the ogres of them attacking or dying, sound of your steps or the sound of landing after jumping.
I look forward to your next improved flash game!