Complex sentence: He is credited for writing 3 episodes of the first season; episode 1.01 "Pilot", episode 1.02 "Allen" and episode 1.09 "Tweener".
Split into simpler sentences: He is credited for writing 3 episodes of the first season. He wrote episode 1.01 "Pilot", episode 1.02 "Allen" and episode 1.09 "Tweener".