Theme:

The theme is an Ultima style rpg (early 80s style rpg) 

Rules:

There are only 2 rules,

1) Don't push yourself to hard to implement any features.

2) Have fun.

Engine Suggestions:

If you need an engine then here are some suggestions,

1) Unity

2) Unreal

3) Godot

4) Gdevelop

5) Game Maker