I get what you are saying, and we have received that input quite a few times already.
I do plan on updating the demo with a couple fixes and QoL features. One of the things I want to do is to add more medium enemies in the overworld after beating them for the first time.
Since the second medium enemy is unfortunately at the end of the demo, it's going to be impossible to add the second one in the overworld, but I will add more of the first one :)