I wouldn't call it AI

... but I added a computer opponent to Bang! Bang! Back!

It is probably the most naive, straightforward implementation possible. It just aims above the next mountain top, adjusts the velocity a little and hopes for the best. (Let's be honest, that's what we all do.)

But it is still a challenging opponent.

To enable it, just go to Game > Configure:

And yes, you can let two computer opponents play against each other, if you like ;-)