Complex sentence: After being passed over for a promotion, an irritated Lowell showed Osborn his work, and Osborn, noticing Lowell's chemical was uncannily similar to the Goblin Formula, immediately fired him and ordered all his work terminated.
Split into simpler sentences: After being passed over for a promotion an irritated Lowell shows Osborn his work. Osborn notices Lowell's chemical is very similar to the Goblin Formula, so he immediately fires him and orders all his work terminated.