Your chapter rank will be decided by your average Mission rank and extra tasks that you do such as not dying or killing every enemy. Keep in mind that you DO NOT have to SS every single mission and you DO NOT have to do extra missions as well.

This game canculates your rank depending on how much points you earned in battle.
You will have to earn as much Bonus points as possible by doing:

• Rush Attacks
  
• Headshots
  
• Focus
  
• Vehicle Attacks
  
• Parries
  
• Reversals
  
• Status Inflictions (Stuns etc)

This is why on Commander difficulty simply defeating every enemy without getting hit is not enough.
And this is why you will have to use Reversal Headshot Spam.



To do so you need to have:

1. Weakest possible machine gun you can find
   
2. "Reversal" ability bought from the Lab

You need to press "Aim" button as soon as you dodge enemy attack and then shoot in the head. While damage output will be terrible you will earn lots of points. This method takes time, but you should not worry about it because Bonus Points will cover the lack of Time Points.



This method, though, has a weak point - Insecticons. They have no heads to shoot. This is why exists Rush Attack Spam/Reversal Attack Spam.

This one, however, gives less points so you might as well try and combine it with Vehicle Attacks.

To do Rush Attack you need to gain max speed in vehicle mode and hold eathier Light Attack button or Heavy Attack Button while charging on your foe.

Reversal Attack - Dodge and then hold Light Attack to launch enemy in the air, or Heavy Attack to launch enemies towards you.

Some fights are missible, missing one will reasult the lowest rank in it and almost guarantee you no SS in chapter.

Chapter 1, Mission 16 - After Mission 14, head into the city rather than the sewers.
Chapter 3, Mission 4/5 - You have to go both paths for Red Energon instead of one.
Chapter 7, Mission 5 - Head left after Mission 4 rather than following the goal marker.
Chapter 7, Mission 7 - Head right after Mission 6 rather than following the goal marker

Some fights will be different from the others:
1. In Chapter 3 for example, there will be a Top-Down section where you will have to kill most enemies as soon as possible instead of trying to collect points.
2. If Mission contains only of flying enemies then this means that you have to shoot them ASAP as well. And don't worry about getting S rank because this will be enough.
3. Agaist giant bosses it is more simple to shoot them in the head from normal focus state, instead of reversal one, because this will help you maintain your distance.
4. Same goes with Shield-Megatron fights as you simply will have no time to go into reversal mode, so your best bet is to shoot him in Normal Focus Mode and hope for the best..

Thanks everyone for reading, I hope it helps! Please feel free to correct me and add your own tips!