A cozy puzzle game where you build an animal house — and learn the hard way that not every animal wants to share a wall.
PETRIS started with a simple thought: the classic falling-block puzzle is fifty years old, and almost every variation since has been mechanical. Faster blocks. Bigger boards. Multiple pieces. New shapes. The math gets reshuffled, but the feeling of the game is always the same — geometry against gravity.
What if the falling pieces had personalities instead?
That's the design seed of PETRIS. Each piece is a small animal: a dog, a cat, or a mouse. They drop into a wooden house grid the same way blocks drop into the well. But unlike colored blocks, animals have opinions about their neighbors. Place a cat next to a mouse and the whole stack rejects them — the cat hisses, the mouse panics, and the piece is removed. Lose enough pieces and the level is over.
The result is a puzzle that feels less like Tetris and more like seating arrangements at a small, awkward dinner party.
The four-piece roster is intentionally tiny. PETRIS is not trying to be a deep tactical game — it's trying to be a game you can fully understand within thirty seconds and keep replaying for weeks. The strategic depth comes from the interaction of just four objects, not from a long list of unit types.
Most of the satisfaction in the game comes from the wall. The wall is a piece you have to plan to use. It costs you a turn and a board cell that could have held a scoring animal, but it lets you cap off a problem zone and keep building safely above it. Players who treat the wall as filler tend to die at level 3. Players who treat it as a tool clear level 7 routinely.
PETRIS is a single HTML file. There is no build step, no bundler, no package manager. The game is plain HTML5 Canvas plus around a thousand lines of vanilla JavaScript, drawn entirely with primitive shapes and no sprite sheets. The whole thing weighs less than a single mid-sized photo.
Every animal sprite is hand-drawn in code at runtime. The dog's ears, the cat's whiskers, the mouse's pink nose, the brick pattern on the wall — none of those are images. They're rectangles, circles and lines composed in a Canvas 2D context. This kept the project light enough to load instantly even on weak mobile connections, and it meant tweaking the look of any animal was a code edit, not an art-pipeline change.
The visual theme is the inside of a small handmade puzzle box. Warm walnut planks, amber stencil lettering, a parchment-cream foreground, and a faint film of grain noise overlaying everything. The board itself sits inside a chunky beveled frame as if it had been sawn from real timber.
The font choice mirrors that — Press Start 2P for the chunky arcade headlines, Pixelify Sans for body copy. Both are bitmap-style typefaces, but they sit in different weight classes, which keeps the headings declarative without making everything else feel like a 1986 marquee.
The cozy palette is also a small commitment. The animals you're stacking are pets, not abstract shapes. The wood-and-amber room around the board is meant to feel like a place where pets would actually live — a warm corner of a house, not a sterile arcade screen.
If you want the full mechanical breakdown — controls, scoring, combos, the lives system — head to the How to Play guide. If you've already played a dozen rounds and want to push your high score past level 5, the Strategy page has the tactics that actually work. Or just drop straight into the game.
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