The following is my personal opinion.
This is the third and final part of the season 2 guide. The last 10 episodes focus mostly on the introduction of the combiner teams into the Autobots and Decepticons roster. But it also features the episode "War Dawn" that contains important backstory about Optimus Prime and the Great War.

M = Must watch: Major plot event and introduction of character/s.
N = New Characters: Not a major plot event but introduces new character/s.
F = Fun Episode: A fun episode to watch.
S = Skip: Boring and or bad episode.
| Title |
Importance |
Comments |
| The Key to Vector Sigma, Part 1 |
M |
Introduction of the super computer vector sigma and the Stunticons |
| The Key to Vector Sigma, Part 2 |
M |
Introduction of the Aerialbots |
| Aerial Assault |
S |
|
| War Dawn |
M |
Optimus Prime's and the great war backstory / |
| Trans-Europe Express |
F |
Fun episode, could have better map of europe. |
| Cosmic Rust |
F |
Deadly rust is killing Megatron |
| Starscream's Brigade |
N |
Introduction of the Combaticons |
| The Revenge of Bruticus |
N |
Continuation of Starscream's Brigade / Introduction of the Protectobots |
| Masquerade |
F |
|
| B.O.T. |
S |
|
