Games like Tetris: what makes a block puzzle last

The Tetris Company’s history dates the first version to 1984, when Alexey Pajitnov built it on an Electronika 60 computer in Moscow. From there it went through a long tangle of rights negotiations and on to Nintendo’s Game Boy, which shipped with Tetris included. The history is told by the rights-holder, so any sales figures in it are the company’s own, but the outline is well established. We have looked at how Tetris’s small ruleset keeps opening up in an earlier piece.

What Tetris set up is a family more than a formula: pieces made of square cells, a grid that fills, and a rule that clears space when you complete a pattern. Games like Tetris vary almost every part of that. Some drop pieces under gravity, some let you place them anywhere on a grid, and some give you fixed pieces to slide around a crowded board and out through an exit. The ones that last share a handful of qualities that have little to do with which variant they picked.

Sources1Source 1The Tetris Company. (n.d.). The history of Tetris. Retrieved September 4, 2026, from https://tetris.com/news/the-history-of-tetris

Tetris can be explained in one sentence: fit the falling pieces together so that rows fill and clear. Nearly every lasting block puzzle has a rule of that size, and its depth comes from the situations the rule creates. When a game needs a tutorial chapter before the first real level, it is usually because the rules are carrying weight that the board ought to carry.

Small rules also resist brute force, which is part of why they stay interesting. Breukelaar and colleagues proved that even the offline version of Tetris, where you know every piece in advance, is NP-complete for goals such as clearing the most rows. Sliding-block puzzles are harder still in the formal sense: Hearn and Demaine showed the general case is PSPACE-complete. For players, that means no known shortcut solves every board, so each board is a fresh problem.

OutBrick’s rule is the same size. Slide a brick home through the gate of its colour, or swap it with a neighbour so three of a colour line up and clear. New pieces arrive over a long game, including crates, ice, locks, moss, statues and counted gates, but each one is a new angle on the same rule rather than a new rule to learn.

Sources2Source 2Breukelaar, R., Demaine, E. D., Hohenberger, S., Hoogeboom, H. J., Kosters, W. A., & Liben-Nowell, D. (2004). Tetris is hard, even to approximate. International Journal of Computational Geometry & Applications, 14(1–2), 41–68.3Source 3Hearn, R. A., & Demaine, E. D. (2005). PSPACE-completeness of sliding-block puzzles and other problems through the nondeterministic constraint logic model of computation. Theoretical Computer Science, 343(1–2), 72–96.

Look at a game of Tetris at any moment and the whole state is in front of you: the stack, the gaps, the current piece and the next one. Nothing important is hidden. That readability is what lets a player plan, and planning is what makes a puzzle feel like thinking rather than luck.

Research on Tetris players shows how much of the skill lives in looking. Kirsh and Maglio watched people play and found they often rotated and shifted pieces to see their options faster, rather than to move them closer to where they would land. They called these epistemic actions: moves made to make thinking easier rather than to change the position. Lindstedt and Gray measured 39 features of play for 240 players, each playing Tetris for an hour, and found that experts stood apart through an integrated mix of perception, decision-making and action, which they called the Mind’s Hand and the Mind’s Eye.

For a block puzzle designer the lesson is to make the state easy to take in and to make trying things cheap. Clear colours backed by shape, pieces that look like what they do, and an undo that invites experiment all help. In OutBrick, colour-blind mode is on by default and stamps a glyph on every brick and gate, and the first undo on every board is free.

Sources4Source 4Kirsh, D., & Maglio, P. (1994). On distinguishing epistemic from pragmatic action. Cognitive Science, 18(4), 513–549.5Source 5Lindstedt, J. K., & Gray, W. D. (2019). Distinguishing experts from novices by the Mind’s Hand and Mind’s Eye. Cognitive Psychology, 109, 1–25.

Tetris gets harder by getting faster. That works because the rules never change: the player loses to their own placements under pressure, and can see exactly where the stack went wrong. Fair difficulty means that when you lose, you can see why. Unfair difficulty is a board that could never have been cleared, a twist the player had no way to see coming, or a rule revealed only after it has cost them.

Speed is one kind of pressure, and there are others. A sliding or placing puzzle can ask for efficiency instead of reflexes, with a move limit in place of a clock. That trades the rush of Tetris at high levels for time to think, which suits a different mood and often a different player. Both are fair when the limit is visible before you start.

Fairness also depends on every board being possible. A puzzle, whether made by hand or generated, should be checked before a player sees it. OutBrick’s 2,000 boards were each cleared by a solver before they shipped, and every board shows its goals and its move limit from the first tap. Difficulty should then rise in steps the player can feel, with new ideas introduced one at a time; our piece on a kinder difficulty curve goes into how.

The smallest unit of Tetris is one piece, a few seconds of decision. The next unit up is one game, which can be short or long depending on skill. That nesting is a large part of why it has lasted. You can play a single game while the kettle boils, and the same game can hold your attention for an hour.

Lasting block puzzles tend to keep a short unit at their core. A single board or round should be finishable in a few minutes, have a clear end, and cost nothing to stop after. Streaks, daily goals and events can sit around that core, but once they start dictating how long you play, the game has swapped its loop for a schedule. An OutBrick board takes about two minutes and clearing one costs nothing, which is the scale we think the genre works best at. There is more on that in why two-minute puzzles feel good.

Whichever kind of block puzzle you prefer, these are the questions worth asking in the first ten minutes with a new one. If sliding puzzles are new to you, how to solve sliding block puzzles is a good place to start.

• Could you explain the rule to a friend in one sentence?
• Can you see everything that matters on the board at once?
• When you lose, can you point to the move that did it?
• Is every level known to be solvable, and are the limits shown up front?
• Can you finish one round in a few minutes and stop without losing anything?
• Do new mechanics arrive one at a time, as variations on the same rule?