Heyawake

Heyawake, meaning 'divided rooms', is a Nikoli puzzle in which the aim of the game is to figure out which cells on the grid have to be painted. The grid itself is divided into rectangular and square rooms of various sizes. A number might be written in some of them.
The grid itself can be any size you wish, but the larger the grid the more difficult the puzzle often becomes. Part if this does depend on the rooms and the number hints that are given though.

The rules are as follows:
- All non-painted cells have to be connected in a single connected system. It does not have to be a loop however.
- Painted cells may never be connected in any way other than diagonally, so only their corners may touch.
- Whenever there's a straight line of connected non-painted cells, they can only be connected this way if they stretch no further than two rooms. So a straight line of non-painted cells going through 3 or more rooms is forbidden.
- The numbers in the rooms indicate how many painted cells there must be within that room.
- Rooms without a number could have any number of painted cells or none at all.

Standard version

Heyawake is a relatively easy game, but some careful thinking may be required for the more difficult puzzles. The best place to start solving the puzzle is often a room with numbers in it.
The higher the number the easier it usually is, as more painted cells mean less possible solutions within this room. Non-painted cells have to be connected after all, so if a 2x3 room against the side of the grid has 3 painted cells there will be one in the top left, one in the middle right, and one in the bottom left. If you change this in any way you will either connect two painted cells, which is forbidden, or lock a non-painted cell inside 3 painted ones and the side of the grid. Since all non-painted cells have to be connected this is forbidden as well.

Like most puzzles this one relies on deduction. Given enough time the solution is usually found be most people, but some of the more impatient or less puzzle enthusiastic people might not bother. Knowing what kind of players you have will help with knowing whether this is a puzzle you should adapt to an RPG setting or not.

Converting it to an RPG setting.

Heyawake is a fun puzzle to adapt to an RPG setting as the possibilities are endless. The aim of the puzzle is basically to create a path. The painted cells could be converted to traps, portals, and similar hassles, as well as hidden loot.

In my example below my character finds herself in a building of sorts. She knows there's a portal in the building that'll get her out of there, she's been given the numbers, and the information on how to solve a Heyawake puzzle. All she has to do is figure out the puzzle and make her way to the portal.

Should my character fail and step on a 'painted cell', she'll discover these cells are actually pitfalls. Stepping in this cell will cause her to plummet into a dark abyss. Where this leads her can be varied as well. Perhaps a room below it, but one without loot, or perhaps she'll simply be teleported back into the building, or maybe she'll have to fight some strange abyssal creature to be granted access back to the building with the portal.

Should everything go well my character will be able to figure out the path to the portal, but there's far more you can do with this than just giving players a route to something specific. In my example there are many paths that lead seemingly nowhere. If my character rushes for the portal by taking the shortest route and thus doesn't explore the side paths, she might miss out on some hidden loot, snippets of lore, warnings, or perhaps something for more valuable.