Many people take RPG's for granted, they have many complex parts to it that have to work perfectly other wise you could get game breaking results. Many people who have never programmed a game don't understand this and I always explain to them all of the different working pieces to it. Now I have an example I can show them. I programmed a simple RPG game in game maker, granted because it was the free version I had to scrap out an entire town I had created for it and focus more on the battle elements. In the game you are in a small free roam map and you come across random battles. As you fight you can use potions to heal you in and out of battle. After each battle you gain an amount of xp depending on the difficulty of the enemy and the amount of enemies. When you level up the amount of xp required to level up again increases by 1.5. Also when you level up your stats increase such as attack, defence and health. Each of these stats actually has an effect in battle when facing an enemy. The enemies also have stats of their own that vary from easy, medium and hard. When you reach level 3 you are faced against the boss and that's about all i have, so here are some screenshots.

This is the simple in-game menu

This is a battle in game with two enemies

This is just the map of where you can move around

 

This is the boss when you reach level 3