Here is a list of adult brain teasers. You can solve some of them online, and they are accessible both with a computer or mobile phone (the browser games). For others, you need to download them to your computer (the PC games) or your mobile phone (the mobile games) before you can solve them.
These adult brain teasers fall in a number of categories, some in only one while others in several. Some of these categories are minimalist puzzles, abstract puzzles, math puzzles, logic puzzles, strategy puzzles, and casual puzzles.
Net Puzzles
Net puzzles are online puzzles for adults, made of nodes, arrows, and numbers. The nodes are labeled with letters, a through z, and the nodes have numbers, 0 through 99. The number of nodes can be between 10 and 20.
To solve a puzzle, you need to arrange the numbers on the arrows so that the numbers on all the arrows that enter each node are less than the numbers on all the arrows that leave that node.
You can try several of them by going here.
SudoKube
SudoKube is a Sudoku game on a 3D cube.
Line Path
Line Path is a puzzle where you need to hit all the squares with one line.
LogiNode
LogiNode is a puzzle that has connected nodes, which are either numbered or blank. Some of these nodes are unlabeled. The goal is to deduce which ones are numbered or blank.
Board
Board is a puzzle with a number of squares arranged in columns and rows to form a rectangle. Each square is either white or black. The goal is to turn all the black squares into white, based on a given pattern of squares.
Yugo Puzzle
Yugo Puzzle is made of jelly blocks you need to move left and right to combine blocks of the same color into one piece.
Tetrix 3D
Tetrix 3D is a puzzle made of three-dimensional blocks of different shapes. The goal is to find the right spot for a given block.
Higgs Boson: Minimal Puzzle
The goal of this puzzle is to rotate pieces to build a particle accelerator.
Cardinal Chains
Cardinal Chains is a puzzle made of a board with numbers in monochrome boxes and colored boxes with the symbol X. The goal is to start with each box with an X and cover the other boxes so that your path forms a nondecreasing sequence of numbers.
Hanoi Puzzles: Solid Match
Hanoi Puzzles are made of hexagonal grids with colored pieces of the same shape. The goal is to stack pieces of the same color so that a piece right above another one is always smaller than the piece below it.
Re-nullum
Re-nullum is made of tiles with numbers. The goal is to combine the numbered tiles.
Minimal Maze
The goal of Minimal Maze is to create a maze by rotating pieces in a given number of moves.
Killer Sudoku
Killer Sudoku is made of several Sudoku puzzles bordered by dashed lines. The goal is solve each Sudoku puzzle so that the sum of the digits equals a given number.
Lines Infinite
Lines Infinite is made of dots, some of which are colored nodes. For each color, there are two nodes. The goal is to draw a path to connect any two nodes with the same color, by covering all the noncolored dots.
Wood Block Puzzle
Wood Block Puzzle is made of ‘wooden’ blocks and a 10 x 10 grid. The goal is to fit wooden blocks of a given shape in a given spot.
Number Match
Number Match is made of numbers in a grid. The goal is to match pairs of numbers until you completely clear the grid.
MultiSudoku: Samurai Puzzles
Each game consists of multiple Sudoku puzzles (up to 5) overlapping. The goal is to simultaneously solve all the overlapping Sudoku puzzles.
Hashi: Connect the Islands
Hashi starts with several nodes labeled with numbers. Each node represents an island, and the number label represents the number of bridges connected to it. The goal is to connect all the islands.
Slitherlink: Loop the Snake
Slitherlink has dots and numbers. The numbers represent clues. The goal is to form one single loop by following the clues. This loop should have no crossings or branches.
Quadrata
Quadrata has a tiled board with a moving block. The goal is to move the block either vertically or horizontally to collect diamonds in a limited number of moves.
Shapez
Shapez consists of a structure (or factories) with moving shapes. This structure can become complex as the game progresses. The goal is to build factories to automate the creation of those shapes.
Insight
Insight has tiled shapes. The goal is to draw a line to divide a tiled shape into smaller shapes.
Minschima
Minschima has triangular, circular, and square shapes with different colors. The goal is to match all targets to restore the broken shapes.
Puzzle & Chess
Puzzle & Chess is made of a chess board and pieces, but its rules are different from chess rules, although the moves are the same as chess moves.
Newton’s Cradle Puzzle Game
Newton’s Cradle Puzzle Game has a number of dark-filled and hollow, dark-bordered balls, arranged on a circuit-like grid. Some of the moves involve moving the balls until they disappear. Part of the goal of this puzzle is to figure out its rules.
Delete
Delete consists of stacked cubes, in many shapes. The faces of some of the cubes are labeled with numbers. The goal is to shatter some of the faces of these cubes according to some rules encoded in the numbers.
Colorgrid
Colorgrid has a number of lasers, mirrors, and materials. The goal is to arrange the lasers and mirrors to get a color combination upon firing the lasers through the materials.
Adjacency
Adjacency has a number of colored shapes, such as squares, triangles, hexagons, and octagons. These shapes are arranged contiguously to form patterns. The goal is to spread colors to adjacent shapes to complete the patterns, with a minimal number of moves.