Robert Louis Stevenson famously wrote that, "In each of us, two natures are at war - the good and the evil."
While this might have been true in the 19th century, Jool has found a way to reconcile these two disparate elements of man's character and reduce them to cute, colour-coded critters that gallivant through levels of arcade-platformer action.
The end result is not an examination of the nature of man, but a satisfying, casual-friendly game with an unconventional approach to Game Overs.
Bird is the word
Jool begins with some rather familiar gameplay. You take control of a bird dashing from left to right at a fixed speed. Tap once to jump, and twice to jump higher. Along the way, you collect items for points and power-ups.
But when you fall, and fall you will, Jool introduces a new level of gameplay. Or, rather, the same gameplay with a twist.
After missing a platform and plummeting to his death, the blue bird transforms into a red monster that looks for all the world like a horned, demonic cheese puff. At this point, you rotate your phone 180 degrees and repeat the same tap-to-jump mechanic - only this time you're dashing from right to left.
Quite the flap
Despite the revolution of your iOS device, the gameplay of Jool is hardly revolutionary.
In fact, after switching from the blue bird to the red demon you'll be doing the exact same thing you were before, albeit from a different perspective.
The creators sensed this monotony, however, and saved the best of Jool's twists for the end.
Each Game Over isn't met by a simple death screen, but by a short (1-3 seconds) animation showing one of your characters meeting a grizzly, and often absurd, end - like being served up on a plate of sushi or crushed between merciless gears.
These death videos ironically provide the most replay value for Jool - which is something of a mixed blessing for the game.
While the cute, cartoony graphics of Jool are sure to appeal to many people, there simply isn't enough meat in the gameplay to keep most players interested in it for long.
Jool isn't a bad game by any means, however. It's polished and quite well done, but it doesn't take any major chances that could help distinguish it as a great game.
If you're looking for a quick, low-investment casual game with a grizzly payoff at the end, Jool won't disappoint.
If you're looking for varied gameplay or platformers that let you play through more than one level, you'll be better served looking elsewhere.