Adventurometer vs Old Greg's Tavern: Which AI Game Master Is Right for You?

Adventurometer vs Old Greg's Tavern: Which AI Game Master Is Right for You?

If you have spent any time looking for an AI game master, you have almost certainly run into Old Greg's Tavern. It is one of the biggest names in the category, with a loyal following and a mascot people genuinely like. So if you are weighing up an Old Greg's Tavern alternative, or you just want a fair Old Greg's Tavern review before you commit, this piece is for you.

We make Adventurometer, so we have an obvious stake in this. We have tried to keep it honest anyway. Old Greg's wins some of these rounds outright, and we will say so plainly. The goal here is a genuine AI game master comparison that helps you pick the right tool for how you actually want to play, not a sales pitch dressed up as a review.

The two products at a glance

Old Greg's Tavern is the casual, mobile-first end of the market. It pitches zero-prep, drop-in play: it is 11pm on a Tuesday, you want to adventure, and you do not want to read a rulebook first. It runs as a native iOS and Android app as well as on the web, it is text-based and round-based, and it leans into a funny, irreverent personality with an actual NPC mascot in Old Greg himself. By mid-2026 it reported roughly 225,000 adventurers, which makes it the fastest-growing AI game master out there. That scale and accessibility are real strengths, and we are not going to pretend otherwise.

Adventurometer is a voice-first AI game master. A narrator we call the Keeper tells the tale aloud, and you speak what your hero does back. Its signature trick is the dial: one adventure, five worlds. The same story plays as candlelit fantasy in Brackenmoor, as failing-station scifi on Helmsreach Station, as reef-and-lantern piracy in Wrecker's Rest, as flooded-rooftop dystopia in Graywater Stacks, or as deadpan seaside absurdity in Brackenmoor-on-Sea, and each world has its own Keeper to run it. Underneath the storytelling sits a deterministic d100 rules engine: the AI narrates, but it never touches the numbers. Every roll, hit and coin is resolved by the engine and written to an append-only log. Solo play is live today, the narration is fully voiced, and our headline feature, provably-fair dice, is shipped and verifiable right now.

Different products, different bets. Old Greg's optimises for friction-free fun in your pocket. We optimise for a table that feels present, mechanics you can trust, and a story that remembers what you did. Here is how that shakes out across the dimensions that matter.

The six-dimension comparison

Now the detail behind each row.

Voice

This is the clearest split between the two products. Old Greg's is text. You read the narration and you type what you do. That is fast, quiet, and works anywhere, which is part of why it travels so well on mobile.

Adventurometer is voice-first by design. The Keeper speaks the story aloud in a real voice, with dice you can see and hear, and you speak your intent back rather than typing it. There is no wall of text to read to yourself. For a lot of players this is the difference between "using an app" and "sitting at a table". Worth being precise here: solo voice play is live today. Synchronous group voice tables, where several people speak around one shared table, are coming soon and not yet shipped. We will not call them available until they are.

If you want a hands-free, spoken adventure, Adventurometer is built for exactly that. If you would rather read and tap in silence on a bus, Old Greg's text format suits that better.

Mechanics

Old Greg's runs simplified mechanics. That is a deliberate choice in service of accessibility: it keeps the barrier to entry low and the pace quick, and for casual sessions it works well. The trade-off is fidelity. It narrates around the rules more than it enforces them.

Adventurometer takes the opposite approach. A deterministic rules engine resolves every roll, hit, wound and coin on a d100 percentile system: your skill is a number out of 100, two dice decide, and success means rolling under it, with critical, special and fumble bands beyond that. The AI narrates the world, but it never adjudicates numbers and never mutates game state directly. The story can bend in any direction the fiction wants; the mechanics underneath stay correct and consistent, and they stay identical whichever of the five worlds you turn the dial to. The cutlass you swing in Wrecker's Rest is the broadsword you carried in Brackenmoor, with exactly the same odds. If you care about your character sheet actually meaning something, and about outcomes that follow the rules rather than the AI's sense of drama, this is the meaningful difference. You do not need to know the rules yourself, though. The engine handles them so you can just say what your hero does.

Dice fairness

This is the differentiator we are proudest of, and it is live now, not a roadmap promise.

A common, articulated fear with AI game masters is that the AI quietly fudges the dice to steer the plot. Old Greg's resolves outcomes on its server, which is a reasonable answer, but there is no way for you to independently check any individual roll.

Adventurometer is built to prove it rather than ask you to trust it. The deterministic engine owns every roll. The AI never rolls. Each result is sealed with a cryptographic commitment before you see it, then written to an append-only log and signed, so any roll can be independently verified. We publish the results on a public roll-stats dashboard at /rolls, where you can see the distribution for yourself and check that the dice are exactly as fair as we say. "Verify every roll" is a line we can actually back up. If you have ever suspected an AI of cheating you out of a clutch roll, this is the answer to that suspicion.

Memory and persistence

Persistence is where a lot of AI game masters quietly fall down, and it is an area where Old Greg's reviewers are candid. The game is episodic with limited cross-session persistence, and users report memory loss and plot drift after roughly 25 rounds, with the complaint that even the top tier could still hit memory limits. For short, self-contained sessions that matters less. For a story you want to continue, it matters a lot.

Adventurometer is built around persistent memory and that same append-only event log. Because every meaningful event, every roll and state change, is recorded deterministically rather than held loosely in a chat context, your campaign has a durable spine. The world remembers what you did. If continuity is what you are after, a story that carries your choices forward instead of forgetting them, this is a real point of difference.

Multiplayer

Credit where it is due: this is a clear win for Old Greg's today. It already ships co-op. You can invite up to five friends through a single link and they play completely free, host-pays style. It is honest to note that reviewers describe the co-op as somewhat thin, more of an add-on than the core experience, but it exists and it works right now.

Adventurometer's group play is coming soon and not yet shipped. The plan is synchronous voice tables with turn-taking and one link for the whole party, which would bring the social, spoken table experience that text co-op cannot quite reach. But it is not live yet, and we are not going to claim it is. Today, Adventurometer is a solo experience. If playing with friends tonight is non-negotiable, Old Greg's is the one that can do it for you right now.

A quick note on mobile

One more honest point that does not fit neatly into a single row. Old Greg's is native on iOS and Android, and that mobile-first polish is a genuine advantage. Adventurometer is currently a progressive web app only. It runs well in the browser and installs to your home screen, but we do not yet have a native app. If a native mobile experience is a hard requirement for you, Old Greg's has the edge there too.

Who should pick which

Pick Old Greg's Tavern if: you want the most casual, lowest-friction pick-up-and-play experience; you value a native mobile app and reading on the go; you love its irreverent personality and want a quick laugh more than a faithful simulation; or you need to play co-op with friends today. It is the friendly, accessible, proven option, and its scale is no accident.

Pick Adventurometer if: you want your adventure narrated aloud and to speak your way through it; you like the idea of one story you can replay as fantasy, scifi, piracy, dystopia or seaside farce just by turning a dial; you care about real, deterministic mechanics that the AI cannot fudge; you are tired of watching a round meter tick down mid-story; you want a campaign that actually remembers what you did; and you want dice you can verify rather than dice you are asked to trust. If "provably fair" and "feels like a real table" are the words that matter to you, this is the one built for that.

Both are good products aimed at slightly different players. There is no shame in trying both and keeping whichever fits your evenings.

Try Adventurometer tonight

You do not have to take any of this on faith, least of all the dice. Sign up and play a one-shot: a ready-made hero, a fully voiced Keeper, and provably-fair dice you can verify yourself. If it feels like the table you have been looking for, forge your own hero with an AI-painted portrait and keep going.

Roll well, and verify it yourself.