AAA ranks are related to secret objectives needed in each mission, this includes Scarlett's challenges, side missions and main story. They reward you with more money and unlock costumes to purchase in the gift shop.

If you fail an objective you can reload a checkpoint before the screwup happened. You can also restart the mission, no need to finish it.

These ones are pretty straightfoward, just finish the mission 3 times for each girl. You'll get a better rank each time with the max being AAA for the third.

To unlock every Scarlett's challenge, refer to this guide :
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=263356645

Scarlett doesn't have any rank associated with her except for her challenges.

Combo Challenge Part 1 : - Hit an enemy with guard break 2-30 times.
- Just guard 2-15 times.

Target Challenge Part 1 : - Hit an enemy with guard break 30 times.
- Just guard 2-15 times.

Survival Challenge Part 1 : - Do 2-15 headshots.
- Just guard 2-15 times.

Katana Challenge Part 1 : - Hit an enemy with guard break 2-30 times.
- Just guard 2-15 times.

Survival Challenge Part 2 : - Hit an enemy with guard break 2-30 times.
- Don't get hit.

Target Challenge Part 3 : - Do 2-15 headshots.
- Use your sub weapon less than 50 times.

Trick Challenge Part 1 : - Kill all enemies.
- Just guard 2-15 times.

Katana Challenge Part 2 : - Kill all enemies.
- Don't get hit.

Survival Challenge Part 3 : - Kill all enemies.
- Crouch and get up 2-20 times (LT/L2+R3).

Katana Challenge Part 3 : - Use adrenaline rush 2-15 times (RT/R2+X/Square).
- Don't get hit.

Combo Challenge Part 2 : - Use adrenaline rush 2-15 times (RT/R2+X/Square).
- Just guard 2-15 times.

Katana Challenge Part 4 : - Use adrenaline rush 2-15 times (RT/R2+X/Square).
- Just guard 2-15 times.

Combo Challenge Part 3 : - Don't get hit.
- Just guard 2-15 times.

Trick Challenge Part 2 : - Just guard 2-15 times.
- Kill all enemies.

Target Challenge Part 4 : - Do 2-15 headshots.
- Use your sub weapon less than 50 times.

Trick Challenge Part 4 : - Do 2-15 headshots.
- Use adrenaline rush 2-15 times (RT/R2+X/Square).

Weapon Challenge Part 1 : - Don't get hit.
- Use your sub weapon less than 50 times.

Target Challenge Part 6 : - Don't get hit.
- Just guard 2-15 times.

Target Challenge Part 7 : - Don't get hit.
- Just guard 2-15 times.

Survival Challenge Part 4 : - Use your sub weapon less than 50 times.
- Just guard 2-15 times.

Episode 1 : - Don't deflect a single bullet (hide behind a dumpster, wait for a salve and move forward).

Episode 2 : - Guard break 2-30 times.
- Don't get killed.

Episode 3 : - Don't get any damage from bugs.
- Don't get killed.

Episode 4 : - Just guard 2-15 times.
- Don't get killed.

Episode 5 : - Kill 5-15 red beeoatch clones.
- Don't get killed.

Episode 6 : - Do 5-15 headshots.
- Don't get killed.

Episode 7 : - Find all Scarlett's locations.
- Don't get killed.

Episode 8 : - Attack only David (only during the boss fight).
- Don't get killed.

Episode 9 : - Don't get stunned.
- Don't get killed.

Episode 10 : - Crouch and get up 2-20 times (LT/L2+R3).
- Don't get killed.

Episode 11 : - Don't get hit by any beam (small red projectiles are blockable).
- Don't get killed.

Episode 12 : - Just guard 2-15 times.
- Don't get killed.

Episode 51 (not required for the achievement) : - Don't get hurt.

Bug Hunt : - Guard break 2-30 times.
- Don't get hit.

A Damsel in Distress : - Do 5-15 headshots.
- Don't overheat the turret.

High Fidelity : - Guard break 2-30 times.
- Don't get hit.

Bonsai : - Kill enemies with Adrenaline Rush 2-15 times.
- Don't get hit.

Time Cursed : - Don't kill any enemy.

Weight Limit : - Kill enemies with Adrenaline Rush 2-15 times.
- Don't get hit.

Gift of the Moon : - Don't get stunned.
- Don't kill any enemy.

Pain on the Train : - Don't overheat the turret.
- Don't get hit.

Man's Little Passion : - Guard break 2-30 times.
- Don't overheat the turret

Reckless Riding : - Don't get hit.
-Kill everyone.
Suda pls.
Protip : You thought killing the true last boss in Cave Story+ was impossible ? You thought clearing Hell in Spelunky was hard ? You thought you'd better eat ♥♥♥♥ and die rather than do a Teleglitch knife only run ? You thought it was impossible to teach Kobe how to be a team player ? F*CKING CASUL.
Prepare to re-assess everything you knew about the world, welcome to our ♥♥♥♥♥♥ hitboxes tour. Next stop : CSGO 1 tickrate servers.

Protip fo realz : You can block bullits.
Running your game at higher framerates seems to make the bike slower, might be wrong though. I've found that I tend to get hit way less if I do everything in advance. For example if an enemy is in front of a barrier, change lane before hitting him. If he's behind, change lane before having passed the barrier.

The Connoisseur (not required for the achievement) : got AAA after finding 13 bottles

Vampire Chillers (not required for the achievement) : got AAA using the charge cannon for the bats and cleared all of the enviroment (barrels, coffins).

Ambient song :
http://www.youtube.com/watch?v=6Z66wVo7uNw

You did it you magnificient bast*rd, you managed to get an AAA rank in Reckless Riding. What's that ? There are other missions too ? Let's be serious for a moment, that's the only mission that you had a problem with in the first place.
Congrats, you got an achievement or something. Go home now.

Credits :
- neosnake101.
- The Hole In You.
- Engineer, he's credit to team.
- Suda 51 and his team for amazing games.