Please, for the love of god, use the dnd rules if you are going to make a dnd game. Jump DOES NOT DO DAMAGE AND KNOCK PEOPLE PRONE, 4th lvl characters do not get two attacks a round without using action surge which is only usable once per short rest. High ground doesn't give advantage. Read the core rule books and use them. Nothing makes a game more frustrating than one that cheats the rules as written.
