The concept of Karoshi (karoo-shi) is not generally considered a very amusing one as it quite literally means to work yourself to death, however in the world of video games we often work hard to avoid dying in order to win. Developer Jesse Venbrux has an obsession with changing this dynamic and iOS gamers may already be familiar with his work on They Need To Be Fed, but when it comes to self-annihilation the Karoshi series is where the theme truly shines.

For those who haven't played the original freeware titles, your character's job is to kill himself. No really, that's his job. However the puzzle-based theme quickly takes a turn for the abstract as players need to exploit gaming specific concepts and counter-intuitive ideas to progress through the game. It's a half-half mix of logic and experimentation that just manages to shy away from being annoying as you finally work out how to succeed.

The puzzle elements range from fairly standard block and switch type platforming to abstract concepts requiring you to control multiple characters while considering options such as purposefully 'trapping' yourself to succeed. At times it can feel like you're playing a multistage version of Syobon Action (Google it), but players are rewarded with a sense of success that's tinged with manic glee as you revel in managing to kill off your player.

Where earlier games in the Karoshi series bordered on immature, this release by YoYo Games shows a level of maturity in its concept that's deeply satisfying to overcome. Thankfully the fun doesn't stop at level 50 and players can throw themselves in to a mini-game series that's just as insanely challenging as the puzzling main game.

Karoshi isn't for everyone, but once you're in it's a hard game to put down and wiping the smile off your face might be as difficult as the game itself.