Claustrowordia is a crossword type game but there are no hints to how to fill the board, instead you're free to fill it however you please. Well there is the small exception of having only a handful of available letters per move to choose from. Longer words score for more and there is a multiplier that increases for every formed word per placed letter.

Every ten placed letters, you can choose a bit of a "twist" in helping you keep the board from not filling (ie. the game ending) and so to speak, delaying the inevitable.

There are six different languages you can play with (game is still always on English only though) and each has its own online leaderboard.