It doesn't work as it's supposed to.
It just keeps adding to the current speed all the time.
I was pretty sure before I even tried the app, that it won't be able to measure the "acceleration" of the device. This sensor is actually just a gravitation sensor to measure the devices attitude. Gravitation just happens to be an acceleration force. Thus the fancy name for the sensor. Bad luck!
Has there been any updates to this app for the 2.0.1 firmware? I would really like to see someone pull off a worthy g-meter app that rivals the paid app they have for sale in the Apple app store.