There's something dodgy about Ninja Pong's [99� / HD] premise. You're telling me that professional ninjas would jump a huge gap onto a tiny platform that has to be manually controlled? And that they'd do it wearing any number of silly hats? I just don't buy it.

You might want to, though. Silly and simple as it might be, Ninja Pong is a fun bit of arcade play that boasts a surprisingly in-depth list of upgrades. Save ninjas, earn shinies, buy things that let you save more ninjas. Sound good?

As master of the platform, you control life and death for your tiny ninja buddies. They need to get from the building or cliff on the left of the screen to its fellow on the right, and you control the only bridge for the gap between. It's one-sided Pong and you control the paddle, dragging it back and forth along the bottom of the screen to bounce ninjas and dodge bombs.

The army of ninjas absolutely refuses to go easy on you. They jump at different speeds, for different distances. When night falls, they all jump at once. It's madness. Some of them jump like jerks, floating in place and falling unpredictable. And all the while, the platform on the right is shelling you with bombs and flaming arrows. It's super hectic, but quite fun.

Powerups can make things a bit easier, but you need to catch them. Do so and you might find your paddle extended, or the ninjas slowed, or a precious life restored. Coins also fall and need collecting if you want to buy yourself something nice.

"Something nice," in this case, is a selection from a list of cosmetic (and adorable) hats for your ninjas, upgrades to your powerups and paddles, and a few things that change the gameplay pretty substantially. Three of the items you can unlock add tapping mechanics to the game, and let you tap the screen in a variety of ways to speed your ninjas up, make them worth more points and destroy bombs.

These modifications (and many of the other unlockables) can absolutely affect your final score, and since you can purchase coins with IAP as well as earning them in game big spenders can give themselves a serious advantage.

Alien Worm has come up with a clever way around that: separate Game Center leaderboards for playing with or without shop items. There's also a leaderboard for the folks who are really into grinding or spending money -- access to the Ninja Diamond League leaderboard is only available to those who pony up 2000 coins, about two dollars or a couple hours worth. It's an interesting strategy for dealing with IAP abuse in a game that's all about earning the highest scores.

There are two ways to play Ninja Pong: Arcade mode and Endless mode. Endless gives you six lives to play with. You can play as long as you want, but let six ninjas die without replenishing your lives and you're toast. Arcade puts you on a 60 second timer during which you'll need to try to earn the highest possible score.

Several factors affect your score. Saving ninjas is good, of course, and saving them in streaks is even better. You can grab multiplier powerups and score powerups. Whipping ninjas to the other side earns you a bonus, as does saving special ninjas and destroying bombs. And most of these things have achievements associated with them, too. At the end of each successful attempt (bombs give you a "game over" without a high score), you also earn bonuses based on meeting milestones.

There's enough going on that it feels like you can improve in any number of ways. If you can get good enough to avoid dropping any ninjas, you'll do well. Do that while collecting all the powerups and you'll be even better off. But even if you don't manage to improve your score, you'll earn coins toward buying the next tempting item in the shop. It's a compelling formula.

Ninja Pong is a simple game. But like many arcade classics, it inspires a desire to improve that will keep it entertaining long after you've seen all it has to offer. If you're the grinding sort, the checklist of an item shop will also prove motivating for quite some time. The simplest games on my phone are the ones I keep coming back to, and I think Ninja Pong will end up on that list in the long run. So check it out, and pop by our discussion thread to let us know what you think.