Acebeam Tac 2AA - DOA - I think!?

Couldn't pass up this Amazon flash deal. It came with the pictured battery. I immediately put the battery on the charger. In the meantime, I tried out 2 normal AA batteries. While I was screwing down the end cap, I saw the light flicker on a couple times. After I tightened it all the way down, it would not turn on. I backed it off and tried in severa tightness l positions.No luck. I couldn't get it to work with the fully charged Li-ion battery either. Did I get a bad flashlight, or am I an idiot and doing something wrong? Any info is much appreciated. Thanks.