New game idea for riot games

I had this crazy idea for a game. It's based off the tabletop game d&d. You have one player that plays as the game master. The game master is given a creation tool that lets them choose different pre-made assets to put together a level for the other players. They could have one tool that lets them shape the terrain of the level kind of like a similar tool from modnation racers. Then they have different building materials to create structures or cover for the other players. Once they create a level layout they like they can place npcs for the players to interact with. Merchants, monster, random citizens, etc. These npcs can be given dialog in real time by the game master. (So say the game master creates a bar scene and the players try to interact with one of the npcs, the game master can have that npc say and respond to whatever the player asked or said. The players could be kind to the npc and receive valuable info, or could piss him off and start a bar fight.) The player characters, which can range from 1 to 4 players, then interact with the scenery. You can play the game casual where the game master can place whatever he want to create a rpg game for the players to play through. Or you can go into a competitive mode where the game masters goal is to kill all the player characters and depending on the player characters numbers and levels the game master gets a set amount of building material to place in the world. I have some other idea for the game but that's the core idea of the game.