onbeat
Say the requested word in time with the beat in quick action challenges.
Engines
The Canvas API is a browser feature for drawing graphics with JavaScript on an HTML canvas element. MDN lists animation, game graphics, data visualization, photo manipulation and real-time video processing among its uses, and says it largely focuses on 2D graphics.
Nothing has to be installed. A game can be one HTML file with a canvas element and a script that redraws the screen every frame, so an agent can write and ship it without a build step. The API only draws, so the game loop, input, collisions and sound are code you or an AI write, or come from a library.
WebGL draws hardware-accelerated 2D and 3D graphics on the same canvas element, and OffscreenCanvas also works in web workers.

Say the requested word in time with the beat in quick action challenges.
Battle a second player with cards on a compact 3×5 grid in short, tense matches.
Face an opponent in a western duel and fire before they do.
Bounce a ball off a paddle to clear glowing neon brick levels.
Water a bare courtyard and find hidden gems through a full watercolor year.
Shoot your way through a Doom-style level using nothing but the scroll input.
Roll a cube across a grid so its inked face stamps only the marked squares.
Play a collection of twelve retro pixel art games in your browser.
Run, jump, and shoot through side-scrolling levels in a Metal Slug-style action game.
Guide your character while a shadow repeats your last move and risks falling into holes.
Play four arcade games in a CRT cabinet and chase shared high scores
Steer a ship while its weapons fire on their own, then extract before four bosses arrive.
Race through quick brain microgames testing reflexes, memory, patterns and logic.
Sing a Renaissance motet together with other players in a shared choir.
Escape a series of crisis rooms by spotting the real fix before time runs out.
Clear mines from the Strait of Hormuz in a shared multiplayer Minesweeper
Beat 50 terrible bosses in card battles, alone or with a friend.
Eat everything in a maze while growing fatter and slower with every bite.
Counted from the 18 games above. A game can name more than one tool or genre, so a list can add up to more than 18.