How did guns change medieval societies?

[Pbartender]

So I ask you, oh great ENWorlders: How did the introduction of gunpowder change real-world societies? What was so great about an unreliable, clumsy, expensive rifle? Why was it better than the good old longbow?

Connections, Series 1, Episode 8

Pay particular attention to parts 1 & 2, where he talks about the development of pikes, muskets and bayonets, and their impact on military tactics.