How to play Rule Stack: a word game with rules
Rule Stack is a free word game you play in your browser. Each round gives you a category and a stack of rules. Type a word from the category that passes every rule, and it drops onto your tower. There is nothing to download and no sign-up.
Play nowThe basics
- Type a word from the category. It must pass every rule. Rules light up as you type, so you can see which ones your word passes.
- Every round adds a new rule, and old rules crumble away.
- Stuck? Skip for a new category. Each skip costs a life. If you have no lives left and you're stuck, the game is over.
- The game never ends. Your score is how high you can build before you run out of lives.
Three example rounds
One rule
Category: Animal
- Ends with E
| HORSE | Passes. It's an animal and it ends with E. |
|---|---|
| GIRAFFE | Passes, and it scores more because it's longer. |
| TIGER | Fails. It ends with R. |
Two rules
Category: Fruit
- 5 letters or fewer
- Has the letter A
| MANGO | Passes. It has 5 letters, including an A. |
|---|---|
| BANANA | Fails. Plenty of As, but it has 6 letters. |
| LEMON | Fails. It has 5 letters but no A. |
Three rules
Category: Country
- Starts with S
- Exactly 5 letters
- Two vowels together, like EA or OU
| SPAIN | Passes. It starts with S, has 5 letters, and A and I sit together. |
|---|---|
| SUDAN | Fails. It starts with S and has 5 letters, but no two vowels touch. |
| ITALY | Fails. It has 5 letters but starts with I. |
Boss rounds
Every 5th round is a boss with a twist rule, such as "No letter E" or a word that has to start with the last letter of your previous word. Beat the boss to earn a life and a power. Long and rare words also fill a power meter.
Opposite rounds
Watch for opposite rounds, because they turn the game inside out: your word must break exactly one rule and pass the rest.
Category: Colour
- Starts with a letter from A to M
- 5 letters or fewer
| PINK | Passes. It breaks only the first rule. |
|---|---|
| INDIGO | Passes. It breaks only the second rule. |
| GREEN | Fails. It breaks neither rule. |
| PURPLE | Fails. It breaks both rules. |
The kinds of rule you'll meet
Early rounds stick to simple letter and length rules. The higher you climb, the stranger they get.
- Letters: Starts with B. Has both A and T. No letter E.
- Length: Exactly 6 letters. 4 to 6 letters. Odd number of letters.
- Patterns: Has a double letter, like OO or LL. No letter used twice. Starts and ends with the same letter.
- Sound and shape: Rhymes with a given word. Vowels and consonants take turns, like TOMATO. Only one kind of vowel, like BANANA or SHELF.
- Word tricks: Hides a smaller word, like FISH in CATFISH. Has no letters from the keyboard's bottom row.
Categories
There are more than 100 categories. They run from everyday ones like Animal, Fruit and Country to narrower ones like Dog breed, Chemical element, Capital city, Pizza topping and Mythical creature. You start with a smaller set and unlock more as you find words, and seasonal categories join the mix at the right time of year.
Scoring
- Longer words score more.
- Rare words score double.
- Fast answers build a combo.
- Runs earn XP, levels and new colours.
Ways to play
- Classic: 3 lives and endless floors. This is the main game.
- Daily stack: the same rules for everyone today, and one try.
- Play with a friend: race a friend online, each on your own device.
- Zen: no lives. Skip whenever you like and just collect words.
- Hardcore: 1 life and no bonus lives, but every point counts ×1.5.
- One category: the same category every round. How many can you name?
- Letter of the day: every answer starts with today's letter.
- Easy: gentler rules, everyday categories and 5 lives.