This guide aims to guide you through the two achievements for getting both the highest and lowest score possible at the end of the game. This guide won't cover any other achievements specifically, though you'll get them by following everything here.

- Genius! - You completed the game with the highest score possible!
- Epic Fail - You completed the game with the lowest score possible!

I've tried to list it in chronological order, but each chapter are rather open-ended, so you may get things in another order.

I've tried to sort each one into three categories:

• Storyline: You can't miss these.
  
• Optional: You should be able to get these if you go back before the end of the chapter. There's no backtracking between chapters though, so they're still technically missable in a full playthrough.
  
• Missable: These are very limited and you may miss the opportunity to get these if you progress further in the chapter.

The high score is for getting 750 points. Obviously do everything for this achievement.
The low score is for getting 190 points. Skip all the optional and missable ones. Make sure you don't accidentally select a dialogue choice that gives you points!

Total: 90pts

Optional
Look at the generator (on the ground).

Optional
Look at the machine (foreground, right side).

Optional
Look at the computer.

Storyline
Charge up the Auxiliary Power Unit (APU).

Missable
Finish the first chapter with 40 points.

High Score: 90/750
Low Score: 10/750

Despite what I said in the intro, I think the only missable achievement in the game (with this guide) is at the beginning of this chapter. Before even talking to the Arrogant Man on the first screen, walk right to the next screen to unlock Great Neutrons!.

Total: 270pts

Optional
Look at your house.

Optional
Talk to your car (Marilyn).

Optional
Exhaust the dialogue with Eli (Arrogant Man). I forgot which to note which question specifically.

Optional
Exhaust the dialogue with Eli (Arrogant Man). I forgot which to note which question specifically.


Optional
Talk to Father Camden about names for his new church.

Optional
Look at the plane crashed into the church.

Storyline
Find the bible buried in the dirt outside the church.

Optional
Talk to the poster near the church.


Optional
Look at the tyre swing near Girder.

Storyline
Trade the bible to Gaius.


Storyline
Listen to the resistance radio broadcast. Find the frequency on the steps of your house, and use the radio outside the police station.

Optional
Look at the flag outside the police station.

Optional
Talk to the statue outside the police station.

Optional
Pick up the bottle on the ground near the crashed bus and automobile.


Optional
Look at the photo of Butch inside the police station.

Optional
Talk to the photo of Butch inside the police station.


Optional
Look at the view of Serenity Valley on the screen of Butch's house.


Optional
Exhaust the second batch of dialogue with Eli (Arrogant Man). It's one of the new options that become available after listening to the resistance radio broadcast.

Optional
Look at the Cloudbuster in the graveyard.


Storyline
Convince Butch to join the resistance.

Storyline
After sending Butch to join the resistance, ask Father Camden if he knows where to find gasoline.


Storyline
Get the truck keys.

Missable
Finish the second chapter with 310 points.

High Score: 360/750
Low Score: 70/750

Total: 80pts

Storyline
Unlock the password on the computer.

Optional
Look at the hankerchief in the small bag (with either character).

Optional
Look at the Strange Object (the wall surrounding the CD) after crawling through the vent with Tachy.

Missable
Finish the third chapter with 390 points.

High Score: 440/750
Low Score: 80/750

Total: 150pts*

* - There's actually an extra +10 points location in this chapter. Even though it's possible to end the chapter with 550 points, You must end the chapter with 540 to get the bonus 50 points. So purposely miss one of the optional 10 points.

Optional
Look at the soldier sitting by the window in the bar.

BY THE BALLS (+10)

Optional
Look at the pool table in the bar.

Storyline
Knock over the flower vase.

Storyline
Pick up the mirror.

Optional
Look at the Aurora Borealis outside.

Optional
Look at box with the radiation symbol in the lab.

Optional
Talk to Bishop about the Illuminati.

Storyline
Go down the Tesla Elevator.

Optional
Look at the wheelbarrow outside the temple.

Storyline
Solve the puzzle granting access to the temple.

Storyline
Talk to the giant crystal.

Missable
Finish the fourth chapter with 540 points. Remember you must have 540 points!

High Score: 590/750
Low Score: 130/750

Total: 150pts

Storyline
Finish setting up the time machine.


Missable
Talk to the crystal in Yonaguni before draining its energy.

Storyline
Drain the Yonaguni crystal.


Missable
Look at the Pieces of Metal on the ground in the Ziggurat of Ur. I'm not sure this one is still possible after picking one up, so I marked it as missable.

Storyline
Drain the Ziggurat of Ur crystal.


Optional
Look at the Image between the lamps in the Pyramid of Khufu.

Storyline
Drain the Pyramid of Khufu crystal.


Missable
Look at the hole where the crystal goes in Chichen Itza.

Optional
Look at the Earth Symbol while it's in your inventory. You can remove the stone even after solving the puzzle.

Storyline
Drain Chichen Itza crystal.


Missable
Finish the final chapter with 690 points.

High Score: 740/750
Low Score: 180/750

Finally, there are 10 unmissable points awarded in the ending sequence.

High Score: 750/750
Low Score: 190/750

The achievement(s) will unlock after the end of the credits.