Muse Spark Open: one prompt, five open models, and a city to blow up

Works first time: auto-attacks, waves, health bar, a game-over screen with stats. Hard: with a simple movement pattern the hero falls in under 20 seconds.

Fixed (one CSS rule): the menu screens were stacked and Start could not be clicked. Enemies die, but the XP bar never moves, so you never level up.

Slowest by far (more than five minutes). No fixes: on a normal screen it plays (enemies, gems, damage numbers, level-ups), but on high-DPI screens (phones, Retina) the hero and enemies disappear.

Fixed (two declarations): it crashed at start-up. Then the most game-like of the four: damage numbers, hordes, level-ups, 60 fps.

Bonus, free in OpenCode for now. Nine minutes of thinking, a cent and a half, no fixes, and it plays: level-ups, gems, damage. It drew plain circles instead of the pixel art the brief asked for.

Sixteen seconds, under three cents. Chunky, but everything asked for is there.

Eighty-one seconds, six times the price. Taller, cleaner, a sunset sky, bamboo and falling petals.

Fixed (one line): detonate threw an error because two arguments were swapped. Then the plaza blows out and the far towers stay up.

No fixes. 48 buildings, 45,000 voxels, 20,000 of them in the air, and a smoke column.