I had several moments while playing EinheitB's Cavernaut [$1.99] where I thought to myself, "This is exactly why I love mobile." It's a game that's probably not going to change the world, but that's okay. It's just a great, tight little experience that could really only exist on this platform.
In Cavernaut you play as a little LEM-inspired craft that needs to make it to the surface of a very deep and complex cave system. (Actually, the craft--and the game itself--was probably more inspired by Atari's classic Lunar Lander than anything humans have done in real life.) Each round begins with your little ship at the bottom of a randomly generated cave, and your job is to tilt and thrust your way up as far as you can before running out of fuel or crashing into something deadly. The fuel needs to be used carefully, since each time you fire one of your jets you'll be expending a small amount of it. It adds up (or subtracts, I suppose) quickly, but thankfully there are refueling stations scattered about that will top you off if you land on one.
That's the gist, but there are also a number of items you can collect along the way. First, there are glowing yellow dots called Luminum Crystals. These contribute to your score, but they also act as the game's currency (which we'll get to in a bit). There are also powerups to collect that enhance your lander's abilities for the duration of your run. Finally, you can seek out little yellow cubes that unlock mysterious artifacts. These don't affect the gameplay at all, but provide a welcome long-term goal if you are a completionist.
All of this is pretty basic stuff, but what surprised me about the game is how it all comes together into a tense, surprisingly strategic experience. Since each cave is randomly generated and the game only shows a little of what's on either side of you (since it's in portrait) you literally have no idea where any of the rocky shafts and corridors lead to. Do you go down the narrow path on the l...