Worldbuilding Exercise

Here's another exercise from the SF Writing Workshop - we were asked to write a passage (that was not purely descriptive), that evoked an alien setting. Alien here meaning anything different from the world as we know it. Here's my scene in a fantasy world:

I watched the meteorite descend and explode in a ball of flame on the left bank, more than a hundred metres away from my little rowboat on the Blue River. Miss. I traced the path of another as it flew through the sky and struck one of the abandoned decaying buildings on the edge of the right bank a couple hundred metres downstream. The building crumbled and the rubble flowed into the river, as a flock of gigantic crows cawed in alarm and rose into the air chaotically. Miss. Thank god for the Carples' terrible targeting. They could destroy forts and castles with their flaming fireballs from the sky, but hitting one man in a tiny rowboat moving quickly downstream was close to impossible. I could sense their frustration and panic as their strikes grew more and more frequent and frantic. Miss. Miss. Miss. Once I was out into the Violet Sea, the Carples would have lost me forever, as well as their King's prized tome on necromancy. Clouds of ash and smoke rose into the air from the spots where the meteorites had struck. I looked through my binoculars towards the sea. Another kilometre or so, and I was free. I adjusted the focus to trace the path of the river between me and its mouth. And then I noticed a small army of Carple Bowmen, identifiable by their deep blue uniforms and sparkling gold crow emblems. The stood on the bridge that hung over the final section of the river. The bridge was a massive structure in white stone. Its monolithic supports grew out of the water and flowed seamlessly into it, as if the entire structure had been sculpted out of a single rock. The archers patiently waited, looking over the river, waiting for me to get close enough for a shot. The Carple meteorites might never hit their target, but those archers, they'd never miss. There was no turning back either. I could jump into the water and hope to escape the archers underwater, but through the crystal water of the Blue River, the archers would have no problem hitting me. Another meteorite struck the edge of the left bank, dangerously close. I could feel fingers of heat groping for me from the point of its impact. Miss. I could see the archers readying their bows. I was almost within their range. The pink rays of the Sun suddenly brightened the area as the clouds moved out of their way. They bounced off the surface of the Blue River, creating a white glare. I hoped the archers would be blinded by it, at least long enough for me to slip past the bridge, but Carple archers are trained to look through such glares. They fit arrows to their bows. Because of the sunlight, I didn't notice one more gigantic fireball descending from the sky. I noticed it only as it flew into my vision, flying down the remaining length of the river, and striking the white stone, turning the monolithic bridge into rubble. The burning archers fell with the broken fragments of the bridge into the water. Hit.