The Bat'leth is a versatile weapon and shield. I have seen some good fight scenes with this and I think it can be very practical if used correctly.
Yes, I'm also sure Jackie Chan could show us how much of a lethal weapon a spoon can be if used correctly.
Here is a so-so demonstration: http://www.youtube.com/watch?v=O7cFeljgO3Y
Aye, thank you for showing us why this weapon would not work.
As we can see on the video, when wielded in two hands, this weapon would lack any considerable force on impact. Length of a weapon more often than not is a critical matter when it comes to dealing damage. This can be best observed with swords. If you hit with part of the blade near to hilt, it may at best push your opponent away. Now hitting with part closer to the tip of the blade could easily knock him out (unless he's wearing plate armour, in which case slashing at him would be just stupid). This also explains why longswords are more lethal than shortswords. The exception to this rule comes in the form of piercing weaponry, such as daggers or rapiers, but usage of this weapon doesn't quite resemble those. Here much better would be a long staff with blades attached at its ends. It would give much better range and strength on impact. If used correctly, it could also drive people away from the short distance. Alternative is simple shortsword. Much faster and much more flexible. Allows you to deliver blows from much greater arch without actually getting uncovered for a longer time. Additionally you have left hand ready to use shield, parrying weapon or another shortsword. Also, when you use weapons like that, you have to deliver the blows using your enire body. That guy uses only his arms, which makes it all the more amusing.
It may somehow work on short distance, but it wouldn't damage plate or chainmail. Additionally I have my doubts as to the leather. And let's be frank. Most people that go into short distance are those who use either shortswords or daggers. Both of those weapons are faster and much more lethal than what was presented on that video. But I guess you could use it to a good effect against armourless fist-fighting monks. But you wouldn't actually defeat spoon-wielding Jackie Chan. As to its defending possibilities, I'd like to see that guy parrying attack at legs. Completely out of range.
Now as one-handed weapon. Bulky. There's just no way to manouver this thing during actual fight. Look at the video. That silly man has problems with delivering a straight blow with that silly thing when he wields it with one hand. And by the way, that back attack is a good example of what not to do during a fight.
If it wasn't for the spread-into-two blades thingy, I could kind of see its use if held with two hands, where one of hands takes the central handle, and used like a sword. It wouldn't be as fast or powerful as
normal equivalents, but at least it might have a chance to damage anything beyond bare skin.