Katana Jack! is an arcade platformer from developer Ivanovich Games, who previously released the fun gallery shooter Operation wow. It has very simple classic arcade gameplay with colorful 2D art and gorgeous painted backgrounds, and it's a pretty solid and fun experience.
Katana Jack! is basically a reimagining or homage to the arcade classic, Bomb Jack. I have not played Bomb Jack, but I'd describe this game as a variation of Pacman with platforming and added variety. Your goal is to destroy every lantern in a level while avoiding enemies. There are special gift boxes with score multipliers, extra lives, or even enemies, and you can even collect a sushi, which turns every enemy into an edible prawn. You can also earn a sushi for hitting ten lanterns in the correct order. You're rated out of three stars for each level, and to get three stars, you have to destroy every lantern in the order in which they light up. You can hit up to five out of order and still get two stars, but any more and you'll only get one.
As you proceed through each level, you'll come across greater varieties of enemies that make you really want to ignore the correct order. I don't know why Jack's katana can only be used to cut lanterns and not enemies, but I'll forgive him. There's no time limit though, so just take it slow, and you'll be fine. You can't really ignore the proper order anyway, because you need a specific number of stars to unlock the next batch of levels. Each batch of levels is accompanied by a different gorgeously painted background.
Due to being an arcade throwback, the gameplay window actually simulates an arcade cabinet, with your movement joystick being fully visible at all times. To add to the arcade-ness of everything, the iCade peripheral is supported. The controls work pretty well, but they definitely feel like classic arcade controls, which can be a bad thing, especially after the touch screen conversion. They don't always feel smooth or responsive and can lead to lots of accidental deaths.
One really cool aspect of this game is that all of the game's art assets were created using an iPad. Likewise, all the music was done with Garage Band on an iPad, and all the voices were recorded on an iPhone. As you play, you'll constantly unlock special videos, showing the levels being painted at hyper speed or showing some 'making of' and 'behind the scenes' features. The game looks and sounds great, but it will likely be too slow paced for a lot of people. I recommend getting it if you're into classic arcade games though, and especially if you've played Bomb Jack. Game Center leaderboards and achievements are supported, and this iOS Universal game can be yours for just one dollar.