I was really excited to see A-Level hit the App Store today—I've actually needed to use a level recently, but I don't have one. And replacing a physical tool with a 99-cent mobile software app is what the future's all about, right? But after grabbing it and giving it a test, it's a well-executed app but with one fatal flaw: you can't re-zero your accelerometers.
If you've played Super Monkey Ball, you know that the EA folks are right when they told us the iPhone devs still have a ways to go before they can tease statistically accurate data out of the acceleromters for precision control of a game. The same problem unfortunately applies to A-Level. Right now, every reasonably level surface in my house is registering around -2 degrees off-centre when a measurement is taken in landscape mode. When you tilt the phone straight up to measure with the bottom, the orientation of the accelerometers shifts, and the inaccuracies EA was talking about become apparent as it swings to the opposite side of the spectrum—around +6 degrees off-center.
A simple re-zero button will help this app immensely—allowing you to take quick comparative readings that aren't as susceptible to error. The developer, Posimotion, says this is on the way—but until then, hold on to your old, non-virtual level.