AthenaJS is a complete 2D Game Engine written using ES2015

Non exhaustive list of features:

• Unlimited number of scenes with an unlimited number of sprites
• Image-based Sprites with any number of animations
• Tiles-based Maps with horizontal & vertical scrolling
• Scene transition effects like Fades, Mosaic can be easily added
• Map vs Sprite & Sprite vs Sprite collision detection
• Map Triggers support
• Sound support with volume and horizontal panning
• Keyboard & Joystick input event supported

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I wrote about it: Optimizing the Canvas HTML5 element

Learn more about AthenaJS here.