Mines of Idle Doomath is a free, single-player idle game about a tiny crew of miners working a very deep shaft. The core action is deliberately simple: you are shown a short math equation, you type the answer, and every correct answer earns minerals. Miss or hesitate and your combo drops, so the tempo is yours to set. Between answering, the game keeps earning on its own, which is what makes it an idle game: you can check in for two minutes or leave it running for an hour and it does something useful either way.
Equations and combos. Each correct answer pays out minerals, and the payout is multiplied by your click power (raised by upgrades) and by your current combo. Streaks build the combo multiplier; the longer you keep going, the more each answer is worth.
Upgrades and miners. Minerals are spent on upgrades that make each answer worth more, and on miners that work the shaft automatically. Hired miners are shown in the crew column next to the mine; you can dress each one in outfits and pickaxes you have unlocked, so every crew ends up looking different.
Gems. A second currency, gems, feeds its own upgrade lines, so progression has two parallel tracks: minerals for the main economy, gems for the cosmetic and quality-of-life lines.
Prestige. When a run gets too big, you can sink a new shaft: this resets the run in exchange for a permanent multiplier that carries over. Prestige is the main long-game loop and is available to every player.
Goals and achievements. The game tracks goals and achievements through the whole cycle, from the first equation answered to repeated prestiges, so there is always something to tick off without needing to grind for it.
The game runs in the browser on this site and on Android and iOS. By default your progress lives only on the device you play on. If you create an account, your save is backed up to the developer's server so you can pick it up on another device, and you can optionally post a score to the leaderboard under a display name you choose. Account creation is always optional; the game is fully playable without one.
The game is free and stays free: there is no paywall on any part of the progression, and everything a paying player can get can be earned by playing. Ads are minimal by design and are the only thing that costs you anything — nothing but a few seconds of your time — and they only ever appear when you choose to watch them: full-screen rewarded ads that you start yourself, in exchange for a bonus. There are no banner ads, no forced or interrupting ads, and no dark patterns such as fake offers or countdown timers.
There is a small set of optional purchases: cosmetic packs (pickaxes, outfits, cave themes) and a convenience pack. These change how the game looks, not how it plays. On mobile they are processed by the app store; in the browser they go through Stripe. Payment details are handled by the store or Stripe, never by this site.
The short version: your save, your stats and the small local crash log live on your device; an account (if you make one) adds a save snapshot and optional leaderboard entry on the developer's single server; that is the whole picture. The full details, including exactly what is stored where and how to delete it, are in the linked privacy policy, and there is a published account-deletion page for people who want to know where to send a deletion request.
Questions, feedback, or an account-deletion request: minus4kelvin@gmail.com. The developer reads it all.