Baba Is You: The Puzzle Game Where You Rewrite the Rules

Finnish developer Arvi Teikari, working under the name Hempuli, built Baba Is You (2019) out of a prototype for a 2017 game jam, and the core idea is simple enough to explain in one sentence: the rules of each level are physical word-blocks sitting on the grid alongside the puzzle pieces they govern, and pushing a word block around changes the rule it represents in real time. Push the block reading IS out of a sentence reading BABA IS YOU and your controllable character stops being controllable. Rearrange FLAG IS WIN into ROCK IS WIN partway through a level and the win condition itself relocates. Every other puzzle game treats its rules as fixed law handed down before play starts; Baba Is You treats the rulebook as just another object on the board, which is a genuinely different category of puzzle design rather than a clever variation on an existing one.

Grammar as the whole toolset

The rule-sentences follow a strict but flexible grammar — noun IS property, noun IS noun, noun HAS noun — and nearly every verb a player might expect from a puzzle game (push, pull, win, stop, sink, melt) exists as a property word that can be attached to, detached from, or transferred between any noun on the board. That means the solution to a given level isn’t “find the sequence of moves that solves this,” it’s “find the sentence structure that redefines what solving even means here.” A level that looks impossible with the starting rule set — a lava field with no visible way across — often has a completely different solution once a player notices WALL IS in a sentence can be rewritten to WALL IS SINK, turning an obstacle into a bridge by changing what category of object it belongs to rather than by manipulating the object itself.

Baba as an unreliable default, not a fixed protagonist

The title character isn’t guaranteed to be the avatar for the whole game, and Hempuli treats that instability as a design feature rather than a gimmick reserved for one gag level. Multiple late-game puzzles require removing BABA IS YOU entirely and reassigning control to a completely different object on the board — a rock, a flag, even a word block itself — which forces a player to abandon the assumption that “the character I usually control” is a stable fact about the puzzle rather than just another rule sitting on the grid waiting to be rewritten. It’s a structural rug-pull that most puzzle games would treat as a twist ending; here it’s simply one more tool in the recurring grammar, deployed repeatedly rather than saved for a single shock moment.

Level design as increasingly hostile grammar

Early levels teach the core IS-sentence grammar in isolation, one new rule type at a time, in the tradition The Witness uses for teaching its own line-puzzle language without text. What Baba Is You does that’s distinctly its own is let the grammar actively fight the player later on: rooms where the word blocks themselves are guarded by hazards that make simple rearrangement dangerous, or where two valid rule changes conflict and only one produces a solvable board state. The game’s hardest rooms, concentrated in its optional Metaverse and Volcanulon areas, frequently require holding four or five simultaneous rule changes in mind at once, tracking how each interacts with the others before committing to a specific push sequence — a cognitive load closer to juggling a small programming language in your head than to a traditional block-pushing puzzle.

The overworld map as the same puzzle, one layer up

The area-select screens connecting groups of levels aren’t just menus — they’re built from the same word-block grammar as the puzzles they contain, and late in the game Hempuli starts letting players manipulate the map itself using identical rules. A locked door blocking access to a new region can, in specific late-game areas, be dissolved by rewriting a DOOR IS SHUT sentence sitting on the overworld grid exactly the way a player would solve an in-level obstacle, which collapses the usual distinction between “the puzzle” and “the menu for navigating between puzzles” entirely. Few games extend their core mechanic this aggressively into their own structural scaffolding; it’s the clearest evidence that Hempuli designed the rule-grammar as a genuinely general system rather than a mechanic scoped narrowly to individual rooms.

Undo, rewind and the cost of a forgiving safety net

Baba Is You offers unlimited undo and a full level restart at any time, with no move counter, timer or scoring system tracking efficiency. That generosity is deliberate rather than an afterthought: because the puzzles here are about discovering the correct rule reconfiguration rather than executing a known solution with precision, punishing experimentation with a limited-undo system would actively work against the design’s whole philosophy of encouraging a player to try a rule change just to see what happens. The trade-off is that the game offers no mechanism at all for a player who wants a sense of mastery beyond “I found the solution eventually” — there’s no time attack mode, no par-move target, which keeps the design pure but also means Baba Is You has almost nothing to offer a player already fluent in its grammar looking for a harder execution challenge rather than a harder logic puzzle.

Where the difficulty argument gets tested

The learning curve here is genuinely steeper than almost anything else in the puzzle genre, and it’s worth being direct about the cost of that: a new player can stare at a mid-game room for twenty real minutes without finding the specific rule rearrangement the level wants, because the space of possible sentence combinations grows combinatorially with every new word block introduced. Hempuli’s mitigation is structural rather than a hint system — levels are arranged on an overworld map with enough optional branches that a stuck player can wander off to an easier room and come back later with fresh eyes — but there’s no in-game nudge toward the specific insight a hard level wants, which will read as a genuine barrier rather than intended friction to players used to Cocoon’s tighter, more curated difficulty pacing.

The editor that turned players into designers

Hempuli shipped a full level editor alongside the base game, exposing the same word-block grammar the campaign teaches and letting players build and share entirely new rooms. That decision matters more here than a level editor typically does in other puzzle games, because the core mechanic is itself a small formal system rather than a fixed set of level geometry — handing players the actual rule-grammar rather than just a grid and some premade objects means community-made levels can explore corners of the rule space the base campaign never touches. Some of the most technically demanding puzzles played competitively within the game’s community were never designed by Hempuli at all, built instead by players who’d spent enough time with the grammar to construct deliberately obtuse rule interactions the base campaign, understandably, never needed to include for a general audience. Few puzzle games make their own design language this legible to the people playing them, and fewer still see that legibility turn into an actively sustained amateur design scene years after release. Hempuli has continued patching the editor and adding new official level packs well past the original 2019 release, treating the base game less as a finished product and more as a stable foundation for a rule-language that keeps finding new applications, a discipline closer to how a small tool gets maintained than how most single-player puzzle campaigns are typically supported once the initial reviews land.

The ancestor

Sokoban — the 1982 Japanese warehouse-puzzle game that gave the genre its name — is the obvious mechanical ancestor of the pushable-block core here, and Teikari has been open about that lineage in interviews. What Baba Is You adds isn’t a refinement of Sokoban’s block-pushing, it’s a categorically different idea: making the rules governing that pushing themselves pushable. That’s closer in spirit to esoteric programming languages than to puzzle game tradition, and it’s why the game reads, to anyone who’s spent time with formal logic or code, as a puzzle about manipulating a small rule-based system rather than a puzzle about manipulating objects within a fixed one. I’ve placed it accordingly in the puzzle game canon as the entry that best proves the genre doesn’t need traditional spatial reasoning to be genuinely, rigorously logical.

The verdict

Baba Is You succeeds by taking a single, small idea — the rulebook is an object on the board — and following its implications with total rigour across hundreds of rooms, never settling for a puzzle that could be solved by simple trial and error once the grammar clicks. The steep learning curve and occasional hint-free walls will cost it players who want a gentler onboarding, but the design never cheats or contradicts its own rules to manufacture difficulty artificially — every solution follows logically from the sentence grammar the game establishes in its opening minutes. It’s on PC, every current console, Switch and mobile, runs identically everywhere given the minimalist presentation, and it remains the clearest single argument for what a puzzle game can be once it stops treating its own rules as untouchable. Its influence is already visible in a wave of smaller rule-manipulation puzzle games that followed, though none has yet matched the sheer combinatorial reach Hempuli got out of a grammar this small, which is the surest sign the design was closer to a genuinely complete formal system than to a clever one-off trick.

Spoilers below

The game’s final area, reached only after clearing a substantial majority of the base levels, strips away nearly every rule scaffold the player has relied on up to that point and presents a mostly empty grid where the only remaining sentence reads BABA IS YOU, with almost every other word block the player would need to win scattered loose rather than pre- arranged into sentences. There’s no new mechanic introduced here — the whole endgame is a test of whether the grammar has actually been internalised, built entirely from tools the game handed over hours earlier. The credits sequence that follows offers no dialogue or written resolution beyond a single closing screen restating BABA IS YOU, framing the entire game’s several hundred puzzles as one long demonstration that the sentence was true, in the most literal sense, the whole time: the game never had a story to reveal, because the rules themselves were always the entire subject.