"The Chosen One" - Animator vs Animation is an original YouTube video that went viral for animating a stickman that turned "intelligent". With today's level of multi-agent reinforcement learning such as OpenAI's multi-agent Hide and Seek, I believed that current technology is sufficient to develop intelligent behaviour.

Introduction Video - Animator vs Animation by Alan Becker

What it does

A Game where the player can challenge the Chosen One. The player can use a gun to aim and shoot the Chosen One. The Chosen One can only dodge bullets at this moment in time.


Agent learnt to camp at a corner:


Agent learnt to dodge Gun bullets:



  • Trained over 1K epochs of 500 timesteps.
  • Chosen One
    • Model: 5 hidden layers, 100 hidden channels
    • Reward function: +1 if surviving, -50 if hit
    • Discount factor (g): 0.995
    • Exploration policy: Epsilon-greedy (e = 0.3)
    • Experience replay: Buffer (size = 10^6)
  • Game Environment
    • State dimension: (25,)
    • Agent: jumps, xpos, ypos, touchingObst, gravityCurrent
    • 5 Entities: x, y, speed, angle
    • Action space: (3,)
    • Agent: left, right, jump
    • Generator: weapon_type, x, y, angle

How I built it

Created a PyGame environment from scratch, consisting of the following entities: Chosen One (agent), Gun (generator) and Bullets (projectiles). Built and trained a multi-agent reinforcement learning model, consisting of a minimax game between Chosen One (agent) versus Generator (Gun).

Main contributions

Traditional reinforcement learning face the difficulty of non-convergence of the agent due to difficult-to-plan curriculum. Using a generative model to play the Gun, the Generator progressively improves, allowing buffer for the Chosen One to improve. This results in a progressive autocurriculum that enables smooth learning of both the Chosen One and the Generator.

Accomplishments that I'm proud of

  • Created Proof-of-Concept of Multi-Agent Reinforcement Learning enabling smooth learning.
  • First time using PyGame to build a game.

What's next for The Chosen One - Multi-Agent Reinforcement Learning

  • Increasing environment complexity - More weapons for Generator to choose and learn, more fine-grained movement mechanics for the Chosen One to master, possible attacks made BY the Chose One.

Final Outcome

This project shows that multi-agent reinforcement learning and progressive autocurricula is useful to enable smooth training of AI in complex environments.


Built With

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