Making Siege of Ages: Heroes of Might and Magic III crossed with an idle game

Every game on Legitsauce starts as a collision between two things I love. For Siege of Ages, the collision was Heroes of Might and Magic III and idle games.

That probably sounds like an odd pairing. HoMM3 is a 1999 turn-based strategy epic — the kind of game where a single map eats an evening. Idle games are the opposite: ninety-second check-ins where numbers go up. But strip each one down to the thing that actually hooks you and they're closer than they look.

What I stole from Heroes III

What kept me up at 2 a.m. with Heroes III (still alive and selling on GOG twenty-seven years later, which tells you something) was never the tactical battles. It was the army-building loop: visit the town, see what new dwelling you can afford, recruit a stack, watch your doom-army get one notch scarier, repeat. The "one more turn" pull is really a "one more upgrade" pull.

And the fantasy underneath it is the slow march from humble to absurd — you start the campaign scraping together a handful of pikemen and end it fielding angels and black dragons. The power curve is the story.

What I stole from idle games

Idle games understand pacing in a way big-box strategy never has. The good ones deliver a felt reward on a strict schedule: something drops within seconds, something unlocks within a minute or two, something structural changes within the half-hour. Siege of Ages adopts that as a hard design rule — coins drop within ten seconds of pressing Play, a new card or upgrade lands within ninety seconds, and a fresh save reaches its first age-up inside thirty minutes.

The collision: seven ages

Smash those together and you get the spine of the game: a side-on lane battler where you spawn units from your base on the left, they march right, and every coin feeds a persistent meta-economy that drags your civilization through seven ages — Dark, Feudal, Castle, Industrial, Modern, Quantum, and finally Planetary, where your caveman cave has become a ringed citadel in orbit. Eighty-four campaign levels, capped by a three-phase fight against the Cosmic Leviathan.

My favorite rule in the whole design: units never auto-retire. A club-swinging caveman you spawned in level 4 can still be on the field in level 80, bonking a plasma walker, until he finally dies in battle. The anachronism is both the joke and the strategy — old units stay relevant through stacked upgrades and sheer numbers, not because the game protects them. Watching a knight, a caveman, and a plasma trooper hold a lane shoulder-to-shoulder is the HoMM3 doom-stack fantasy compressed into a browser tab.

How it was actually built

I'm one person, so the production pipeline matters as much as the design. Two AI tools carried most of the weight:

Art: GPT image generation. The unit, enemy, and base art across all seven ages was generated with GPT's image model, working from a design document that specifies every sprite down to silhouette and palette — the readability rule is that no two units in the same age share a silhouette, so each one is identifiable at thumbnail size from shape and color alone. Generated art needed real post-processing, though. Every batch came back with a consistent warm yellow cast, so the whole set went through a gray-world auto white balance — dialed to 35% strength, because a full-strength correction shoved skin, leather, and bronze into a blue tint that looked worse than the original problem. Lesson learned: AI gets you 90% of the way, and the last 10% is still squinting at pixels.

Code: Claude, plus my own hands. The large majority of the GDScript (the game runs on Godot 4.6, compiled to WebAssembly for the browser) was written by Claude working against that same design document, with me doing code review, integration, and the manual tuning passes that no model can do for you — balance curves, input feel, the difficulty math that makes the final boss demand a real grind instead of folding to a fresh save. Every system ships with headless unit tests, which is what makes this workflow safe: when the test suite is green, AI-written code and hand-written code are held to the same bar.

Did the collision work?

You can judge for yourself — Siege of Ages is free in the browser, no download, sessions of three to eight minutes. My honest take: the HoMM3 itch is real in the meta-layer (the moment a new age unlocks its roster is pure "new dwelling day" energy), and the idle-game pacing keeps the early hours from sagging the way grand strategy openings do. If you grew up alt-tabbing out of Erathia, this one's for you.