Hi, I am interested in your project.
If you have all the assets, I think a basic setup of the game would take around 10 hours. If you have no assets, a basic setup of the game, moving and attacking would take about 5 hours. Implementing a small data base (from where you could control the life, damage, resistances, etc) of the monsters, maybe another 5 hours.
If selected, I would like you to know that I will add all the necessary comments, so you can implement forward on your own as well.
Thank you for your consideration and good luck with your project,
Stefan