This level is running along a large waterfall. As you travel along the area, various logs will fall off the waterfall. You need to hit the letters to get their points

Bronze Medal Requirements:
Earn a no-miss capture streak of 4 Pokémon

Silver Medal Requirements:
Destroy all the logs falling from the waterfall and earn a no-miss capture streak of 8 Pokémon

Gold Medal Requirements:
Destroy all the logs falling from the waterfall and earn a no-miss capture streak of 20 Pokémon