I added some new stuff and the first part of the tower is almost finished.

1. There are now five levels of the tower

2. You can fight a first boss battle on the fifth floor (I still have to give it skills, though)

3. There’s character progression, i.e. you increase your stats by leveling up

4. New enemies

5. The game saves automatically whenever you enter a new floor

Next up is the menu to use items outside of battle and the boss skills. :)