That shouldn't be happening if you are in the first area. Let me make a new save really quick and see for myself!
Viewing post in Lusty Tales - Monster Guys Awaken DEMO comments
Yea I don't know what is going on as I just made a new save and fought the first two monsters in the first part of the forest and if anything I one shotted the snake man. Of course I did notice that without the gear from the chest in the house that I couldn't win. As I equipped the fire tome and staff and sword and I simply used a fire ball spell and won the snake man fight with ease. So I am going to assume that you may have missed the chest or forgotten to equip the items and I don't blame you as I should have added a event that makes it so you have to get the chest before being able to leave.