In my case the internal shock sensor (a tiny spring-shaped conductor around a spike on the PCB) is very insensitive: the lamp turns off every three minutes while cycling, only switches back on to a very strong tapping. Maybe the sensor should be short circuited, because in this state the auto power off (or autostart) function is a bug, not a feature.
More detailed technical info: the main led current is not stabilized, it varies between 1A - 0,2A (as the battery voltage drops 4,2V to 2,8V), the brightness decreases in a similar ratio as the battery discharges. The maximal luminous flux can be about 350..400 lumen - based on the measured led current and Cree XP-G datasheet - in state '100% main light', but on average around 260 lumen (with 3,7V typical Li-polymer battery voltage and 2,2W led power). In power saving / 50% mode the leds PWM frequency is around 260 Hz.

I am impressed by the build quality. It has 1200 mAh battery and Cree white led and two small red led. With holder has 72 gr weight. Nice light patern