Puzzle games that make you think

This list is for players who would rather work something out than react fast. Some of these are calm and have no clock at all. Others put a timer on the thinking, which is a different kind of pressure. All of them are free, run in a browser and save your progress or best scores on your own device. We have said which ones need a keyboard and which play just as well on a phone.

PIPEWORKS

PIPEWORKS gives you a grid of scrambled pipe pieces, an inlet on the left and an outlet on the right. Click or tap a piece to turn it a quarter turn, and the moment the route connects, the water flows through. The catch is that the room is flooding from the bottom while you work. There are six hand-built rooms, each adding one new idea such as bolted pipes or crossovers, and after that the game builds new rooms for ever, growing up to 11 by 9.

It is a clean, quick logic game, and every room is guaranteed to have an answer. Tip: a piece with four orange bolts cannot be turned, but it is always part of the route and already facing the right way, so build out from it.

SWEEP

SWEEP is minesweeper on a clock, one board after another, each a little bigger and denser than the last. You pick a starting size, from Tiny 7 by 7 to Huge 16 by 12, and one of four difficulties, from Easy at 11% mines to Brutal at 26%. Your first click is always safe, along with the eight squares around it, and the clock only starts when you make it.

It is honest about its hardest settings: at Hard and Brutal, some positions cannot be solved by logic alone, and a quick guess can beat a long stare. On a phone, press and hold to plant a flag. Tip: once the flags around a number match it, click the number to clear all its other neighbours at once. Check your flags first, because the shortcut trusts them completely.

BOMB SQUAD

BOMB SQUAD puts a ticking bomb and a paper manual on your desk. Each bomb has one to four small puzzles, such as wires, a button, a keypad, a colour-sequence game and a hidden maze, and the manual tells you how to solve each one, depending on the serial number, batteries and lights on the bomb's casing. Every wrong move makes the clock run 25% faster, and three strikes set it off. There is a 20-bomb campaign, an endless mode and one daily bomb that is the same for everyone.

It is the most demanding game here, because you have to read carefully under pressure. You play both roles yourself, so no second player is needed. Tip: read the serial, the batteries and the lights before you touch anything. Nearly every rule asks about them.

ONE TILE

ONE TILE is a pixel heist seen from above. Each level is one room: reach the safe, crack it and get out through the exit without being seen. Guards, cameras and lasers all run on fixed loops that repeat exactly on every attempt, and their view cones are drawn on the floor. There are 24 jobs across a bank, a museum, a casino and a penthouse, each with three stars to earn.

It is a puzzle you play in real time. Each room is built with one or two safe paths, and being caught just puts you back at the door. On a phone it plays sideways, with your finger held on the side you want the thief to run. Tip: the safest place in a room is often one tile behind a walking guard, because he only looks the way he is facing.

BLOCK ROYALE

BLOCK ROYALE is the familiar 8 by 8 block puzzle, but every clear is scored like a poker hand. Cleared blocks give Chips, clearing several lines and keeping a streak raise the Mult, and you need to hit a target score in 20 placements each round. Between rounds a shop sells charms that bend the rules and one-shot glyphs that can rescue a full board, and eight bosses change the rules again. There is also a daily seed and a Zen mode with no targets.

It is the one to pick if you like building a strategy over a whole run, not just one board. It works on a phone in either orientation. Tip: charms fire left to right, so put the ones that add Mult first and the ones that multiply it at the end.

MIRROR DUEL

MIRROR DUEL looks like a fighting game but plays like a puzzle. You control your cyan fighter, and the magenta MIRROR copies every input you make, flipped left to right. In an even room every hit would trade evenly, so each of the eight stages is lopsided on purpose: spikes on one side, a wider pit on theirs, ice on their half. Your job is to find where the same move hurts them more.

It is single-player only, since the other fighter is always your own input. There are brief white flashes on hazard hits and knockouts. Tip: read the one-line hint at the top of each stage. Hazards decide fights, so line up a heavy attack that sends the MIRROR into the spikes or the electric wall.

WORD BLITZ

WORD BLITZ is a 90-second word hunt on a four-by-four grid. Drag through touching letters to spell words of three letters or more, or simply type them on a keyboard. Long words score far more, with a length bonus up to four times for eight letters, and each board has bonus tiles that double a letter or triple a whole word. There is a fresh board every round and one daily board that is the same for everyone.

The results screen shows the common words you missed and where they were, which is a good way to improve. Tip: if you go blind, rotate the board. It does not change the words, but seeing the letters at a new angle often makes them jump out.

MERGE

MERGE is the calmest game on this list. You drop fruit into a glass jar, and two identical pieces join into the next size up, with real physics deciding how they roll and settle. There is no clock: you only lose if a settled piece stays over the line at the top for more than 1.2 seconds. The chain runs to a thousand stages, with the fruit starting again in new colours every eleven.

It is a good one to wind down with, and a tap drops the fruit on a phone. Tip: keep the big pieces at the bottom. A large one stuck on top of small ones blocks everything beneath it.

If you want no time pressure at all, start with MERGE or the Zen mode in BLOCK ROYALE. If you like a clock, PIPEWORKS and WORD BLITZ are quick rounds. If you want a real test, try a campaign in BOMB SQUAD or the later jobs in ONE TILE.