A puzzle game that was originally released for the Sharp MZ in 1985. However, the most well known version of the game was released in 1990 for the original Game Boy. The Game Boy version was later re-released via the 3DS Virtual Console.
The Game Boy version features two characters (a boy and a girl) that have been cursed with cat-like features, they must traverse puzzle rooms to find and defeat all the enemies. There are 100 levels in total; 99 of which may be played in any order, the final level can only be played after the completion of the other 99. Player can also generate a password that will recall what levels they’ve already completed.
The rooms gradually increase in difficulty from completely straightforward A to B levels to incredibly complex patterns of boulders, ladders, and destructible walls.
In the Game Boy version, the player chooses between playing as the male cat or the female cat. However, there are several levels where the player plays as both characters simultaneously; the player must switch back and forth between them to maneuver through the puzzle room.
Each level features at least one enemy; the goal being to reach all enemies and destroy them. The enemies cannot harm the main characters, so the difficulty is in finding the correct route through the level without getting stuck. If the player believes they’ve made a mistake, they can rewind time as far back as they please and try again.