Further to this, I have had reason to write out the rules to 16 nikoli puzzles. Any feedback on what I've done would be hugely appreciated!

Akari

Place some light bulbs in the grid. Each numbered black cell indicates how many lights bulbs are adjacent to that cell. The light bulbs emit rays that travel horizontally and vertically until they hit a black cell or the edge of the grid. Each white cell should be illuminated by a light bulb, and no two light bulbs should illuminate each other.

Fillomino

Place a number in each cell of the grid, so that each number is contained in a polyomino of that size. Polyominoes of the same size must not be adjacent via a common cell-edge.

Hashi

Connect each of the numbered islands in the grid via horizontal and vertical bridges. Each island has that many bridges leading away from it, and at most two bridges are allowed to connect a pair of islands. There must be a sequence of bridges that links one given island to any other.

Heyawake

Shade some cells in the grid. The grid is divided up into rooms. If a room is marked by a number, then there must be that many shaded cells within it. Shaded cells should not share an edge, and the remaining unshaded cells should form a connected area via horizontal or vertical paths. The unshaded cells should not traverse more than two rooms in a straight line.

Hitori

Shade in some cells in the grid so that in the remaining unshaded cells at most one of each number appears in any row or column. Shaded cells should not share an edge, and the remaining unshaded cells should form a connected area via horizontal or vertical paths.

Kakuro

Place a digit from 1-9 in each white cell in the grid so that the sum of each horizontal/vertical group of cells equals the number given on its left/top. Digits must not repeat within any sum.

LITS

Place exactly one of the four tetrominos (L, I, T and S) in each marked region of the grid by shading in some squares. Tetrominoes of the same type, up to both rotations and reflections, must not be adjacent via a common cell-edge. The resulting shaded cells in the grid should form a connected area via horizontal or vertical paths, and there should be no 2x2 area of cells completely shaded.

Masyu

Draw a single closed loop in the grid, travelling horizontally and vertically through the centres of each empty cell it passes through. The loop must not intersect/overlap itself. The loop should also pass through each circle in the grid. At a white circle, the loop should travel straight through and make a 90° turn in the cell immediately before or after. At a black circle, the loop should make a 90° turn and extend in the relevant two directions for at least two cells.

Numberlink

Connect matching pairs of numbers in the grid with a line which travels horizontally and vertically via the centres of each cell it passes through. Any given line must not intersect/overlap itself, or any other line.

Nurikabe

Shade some cells in the grid, such that the shaded cells form a connected area via horizontal and vertical paths, and so that there are no 2x2 area of cells completely shaded. The remaining unshaded cells should form several connected islands. Each island should contain exactly one given number in the grid, and this number represents the number of cells of its corresponding island.

Ripple Effect

Place a number in each cell in the grid. The grid is divided up into several regions, and each region should contain the numbers 1-n exactly once, where n is the number of cells in a given region. Any given number m in the grid should be at least m cells away in a horizontal or vertical direction from any other instance of m in the grid.

Shikaku

Divide the grid into rectangles so that each rectangle contains exactly one number. Each number represents the number of cells of its corresponding rectangle.

Slitherlink

Draw a single closed loop in the grid, travelling horizontally and vertically between the lattice points. The loop must not intersect/overlap itself. Numbers in some cells of the grid indicate how many edges of that cell are contained in the loop.

Sudoku

Place a number from 1-9 in each empty cell in the grid such that each row, column and marked 3x3 box contains each number exactly once.

Suraromu

Draw a single closed loop in the grid, travelling horizontally and vertically though the centres of the cells it passes through. The loop must not intersect/overlap itself. The loop begins (and ends) at the circled number, and travels perpendicularly through each of the dotted gates exactly once. The gates are labelled in the order that the loop passes through. The circled number indicates the total number of gates.

Yajilin

Draw a single closed loop in the grid, travelling horizontally and vertically through the centres of each empty cell it passes through. The loop must not intersect/overlap itself.

Any empty cell the loop does not pass through must be shaded in. Shaded cells must not share an edge. Some cells have numbered clues; these indicate how many cells in the given direction are to be shaded.

Thanks for taking a look - any comments/criticisms are more than welcome!