Ninjatown: Trees of Doom! is a game that could devour my waking hours, if I allowed it. Fiendishly simple to play, it's one of those games that makes it so easy to tap the button and keep playing, creating hours of life-suck. The major draw continues to be the characters that made the original Ninjatown a fun game to watch and play. Animator Shawn Smith has a great style that compares to the Uglydoll designs most people able to fog a mirror can appreciate. Wee Ninja is back, along with some familiar and some new friends and enemies. Expect to see Mustachio, and even hitch a ride on his hirsute conveyance. Ol' Master Ninja is always nearby to bail you out, and several costume changes are available to be unlocked by skilled players. The full package comes with a musical backdrop that sounds appropriately Eastern and mysterious, plus the sound effects you'll come to connect with specific enemies and events. There are important visual and audio cues in Trees of Doom! connected to timing. Not that you can't navigate perfectly by sight, hearing the sounds helps to time some of the trickier sequences. At other times, you'll be given some major hints about upcoming dangers, such as the volcano projectiles that spark on the left, right, or middle before they come plummeting down. You'll have to get used to some of the game's measurements, judged in a relative fashion rather than by specific dimensions, since getting things wrong will quickly result in a do-over. The fact that the game's layout seems to change each time you come back to it makes it harder to memorize patterns and anticipate challenges. We loved the random feeling of each stage, especially because it takes the tedium out of starting over. Seeing the same elements combined in different ways doesn't sound that exciting, but it beats the pants off having to watch the same scenery go by for the millionth time.

At its heart, the first Ninjatown was a tower defense style of game. Trees of Doom! has less clear parentage, but we'd have to classify it as a sort of 2D Platformer. There have been climbing games before, and classic arcade games that focused on navigating your way up, across, or down the screen while navigating obstacles and collecting objects. What makes Ninjatown: Trees of Doom! different is the ninja connection, and the idea of climbing for the sake of climbing. Sure, there is a reason for this Wee Ninja to be headed up to the treetops, but the urge to climb is about all you need to get things rolling here. The orientation of the game is strictly portrait, and if you can imagine a typical three-column web layout, you'll be spending your time hopping between the far left and right-hand column. In this case, those columns are tree trunks that you can cling to, ninja-style. You can hang around indefinitely on the side of the screen, but you only score points for moving.

The Classic and Timed modes are pretty easy to distinguish. In the first, you get points for climbing, and have no time pressure. The other mode is all about moving quickly through a specific section of the game, and in both instances you'll get the chance to compare your score through the game's leaderboard, if you choose to publish scores. If the idea of jumping back and forth on-screen sounds too simplistic, you have to realize that most platforming games just aren't that complex. The best ones understand that theme-and-variation can make for some incredibly fun action. How many enemies were there in the original Crash Bandicoot games? A dozen or so? The really interesting thing in Ninjatown: Trees of Doom! is how it keeps you moving forward by mixing up obstacles, climbing surfaces, enemies, and power-ups so seamlessly. First, you learn to avoid one spear-throwing enemy, then you come across three of them working in a pattern, then five, etc. The same holds true for navigating obstacles on the tree, forcing you to think creatively about when and where you jump left and right. A simple premise makes for really engaging gameplay.

Ninjatown: Trees of Doom! has a knack for ratcheting up its challenge slowly, like the storied technique for cooking a frog; increase the water temp gradually, and the frog never notices... The validity of this frog business is disputed, but there's no denying that Ninjatown: Trees of Doom! slowly brings you from wet-behind-ear neophyte to expert in a few hundred feet of climbing. The 1,000-foot mark is a placeholder that you'll be able to return to without retracing your steps from the very bottom, and represents a good achievement. Reaching this waypoint means learning a lot of technique and timing, some of which you just have to bring to the game. If you've never been very good at a Platformer, Trees of Doom! is likely to frustrate you in the end. There's a lot of good fun to be had here, but twitch reflexes ultimately rule. Most challenges below 1,000 feet can be resolved with patience and deliberation, but the game starts to throw obstacles at you that force your hand and require split-second timing. The best example is a falling projectile from the far-away volcano that forces you to move left or right, and can even clip you mid-jump, as it falls down the center. Platform fans will love the action and find that the iPad is perfectly adapted to this style of game.

There are only two points of contact in Ninjatown: Trees of Doom!, on the right and left side of the screen. You'll tap on either side to make your ninja jump, and the angle of this jump is fixed. You'll learn to judge this and time your jumps, requiring a bit of climbing at times to make a grab for some floating power-up, or to land in a specific spot and avoid an obstacle. The only time you get to actually influence your jumping angle is when you grab a tree and can bend the branch in such a way that it shoots you into a specific spot, conveniently marked with a large arrow... Everything like the tree or a sometimes-helpful bouncing mushroom (homage to Mario perhaps?) is very easy to use, because you'll just end up automatically interacting with the object as you climb. This simplifies the controls, removing any need for a "use" or "action" button, and also eliminating the need for timed jumps. Trees of Doom! brings all the best elements of a Platformer into its gameplay, while maintaining a properly simple design that suits the scaled back interface. Beyond all this, it's just a really fun game that will have you tapping madly for hours on your iPad in search of yet another milestone for Wee Ninja's big climb.