Ancient weaponry, how to arm yourself when only sticks and stones are available

The sling, King David's weapon of choice:

The atlatl, the signature weapon of Cro Magnon man:

Archery starting from nothing out in the woods:

The greatest modern archer by way of contrast. Howard Hill was the guy doing all the trick archery for Eryl Flynn's old Robin Hood and Ivanhoe movies in the 1930s:

The atlatl is one of the major reasons that the Neanderthal no longer rules this planet. Hominids such as the Neanderthal generally lacked the kinds of shoulders you would want for throwing a javelin or using something like an atlatl, and were limited to stout thrusting Spears. Humans are basically aquatic mammals and the motion to throw something like a javelin or to use an atlatl is essentially the same motion we use for swimming.

Compared to a bow, an atlatl was not as accurate but was probably more lethal. Archery requires using arm and upper back muscles; somebody using an atlatl properly appears to be using pretty nearly every muscle in his body.