Of course, I don't mind.
I know that the gameplay is still very much in an early stage, so I won't comment on it too much.... and absolutely feel free to disregard these comments if you already have plans to implement these.
1. I will say your demo would really benefit from sound effects. Sword, jump, enemy, footsteps. These all provide important feedback to the player. Additionally, for damage to or from an enemy, consider adding some sort of feedback in the form of sound or screen effects (like a split-second pause) to give the player an indication of how things are going. I'd say this is the most important thing to implement before releasing the next Oz and Zo demo.
2 . I'd recommend building up the setting of this early section of the game to better establish who Oz is and what's happening around him. Assuming this demo starts at the beginning of the game, we want to know more about Oz and his family and town. This doesn't have to be given in exposition. The easiest way to do this would be to show the "pecking order" of Oz's world. What's his financial situation? His clothes, speech, and demeanor indicate middle class but his home looks rustic and rundown. His athletic skills indicate he is super-human which should put his family in a high-earner status unless the rest of the world has greater athletes running around doing things. He has a sword (?) but we have no indication where the sword is from. Is he from nobility? Supernatural? Is it an old rusty machete? I'm certain you have this lore sorted out already but the demo could benefit from showing how the world treats Oz's family and how they respond to it. My favorite example of this is the game "Wild Arms", which manages to have great intros for all 3 of its protagonists. These indicate - in a short amount of time - class, health, family, desires, worries, and fighting abilities.
Since this is a video game, I would use the first mission objective to show the player how Oz gets his weapon and use that as an opportunity to show Oz's personality and lifestyle. For example, if he's poor when mom tells him to cut the grass make it a point to show that Oz needs to get the old rusty machete from the shed because that's all they have. Or if his family was once nobility have him go into his dad's old warchest and get the ceremonial sword because that would be so much faster than an old knife. Or if he has secret powers that can never be shown maybe have Oz throw out the cutting tool his mom gave him because he has a super striking power that beats non-magic powers anyday. These are just general ideas but they go a long way to establish the world and the characters better.
These were the 2 main things that jumped out to me. Please let me know if you'd like further feedback and I'd be happy to provide more. Again, I think there's a lot of potential here. I look forward to the next demo.