This is my first attempt in making a game guide ever. And English is not my native language so you might find some lingual error.

You may leave a comment for improvement or correction to my guide.

Thanks.

For completing the achievement, you don't have to buy any of the DLC's.

Version Info:
Version 1 - 21 August 2015

Credits:
Choplifter HD - To the developer, publisher and all related parties.
Steam - For hosting and enabling this guide.
Guide Icon - Taken from - Deviant Art[pooterman.deviantart.com]
Screenshot - All the screenshots are mine, mind the quality.

Achievement List and the description

Sorted by community completion percentage

Zombicide - Kill 1,000 zombies
Trigger Happy - Kill 100 enemy soldiers on one level, without restarting the level
Oopsies - Complete a level by killing all the rescuees
Unfriendly Fire - Kill 10,000 enemies across all the levels
Mission Accomplished - Complete the game on NORMAL
Get the Scoop! - Save Scoop on every level he is present
All Star - Get 5 Stars on all levels
Superhero - Complete Desert Rescue without letting any rescuees die
Goat for IT! - Make 100 goats faint
No Stone Unturned - Find all secrets
Dinner is Served - Kill 1,000 chickens
Pacifist - Complete all "Escape" missions without killing anyone

You will earn these achievements over the gameplay

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1. Zombicide - Kill 1,000 zombies
2. Trigger Happy - Kill 100 enemy soldiers on one level, without restarting the level
3. Unfriendly Fire - Kill 10,000 enemies across all the levels
4. Mission Accomplished - Complete the game on NORMAL
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You will earn these achievements over several tries

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5. All Star - Get 5 Stars on all levels
6. Oopsies - Complete a level by killing all the rescuees
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Here is the tips for the other achievements
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7. Goat for IT! - Make 100 goats faint
8. Dinner is Served - Kill 1,000 chickens
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Mission : Operation Alpha Freedom - Prison Break



After starting of the mission, before the river crossing, there are lots of goats and chickens on the plateau.

Chicken will respawn after being killed, so you just gun them down until the achievement is unlocked.

The goat however are not respawning. You have to restart (by dying or completing) the mission. The kills however are not accumulated by restarting the game from the menu.

To can check your kills stats from the Stats in the Title Menu.

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9. Superhero - Complete Desert Rescue without letting any rescuees die
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Mission : Operation Bravo Breakout - Desert Rescue

This is pretty tricky mission, I'm suggesting you to replay this mission with "Old Glory" after you have unlocked that chopper.

The first priority, is to save the farthest group first since they have wounded in the group. The mission which needed you to destroy enemy target can be accomplished later.

Since this mission will required you to rescue numbers of prisoners, please be careful when landing your chopper (I did killed my rescuees few times before unlocking this achievements).

Also be reminded that your missile explosion also can kill the rescuees.

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10. No Stone Unturned - Find all secrets
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You may need to complete the all of the Hidden Objectives. I'm not really sure if these achievements is related to other Easter Egg in the game.

I've unlocked this achievement together with Get The Scoop!

Hidden Objective - Where's The Beef
Mission : Operation Alpha Freedom - A Snowballs Chance



After scoop location (Refer to Get the Scoop!), there will be a bunker with AA placement. Hover and turn to side and destroy the fence to liberate Super Meat Boy. Pick him up and send him to base.

Hidden Objective - Kill them before they multiply
Mission : Operation Bravo Breakout - There is no place like AAAhhh ZOMBIES!

Kill numbers of zombies, after completing the task, the red news marquee will mentioned that zombies populations has been thinned out.

Hidden Objective - Find the Blockhead stranded on island.
Mission : Operation Charlie Takedown - All on the table



Starting the mission, from the base, fly to the right side and rescue Steve from Minecraft i.e the blockhead.

Some Easter Egg I've discovered in the game is:

Zombie Helicopter
Mission : Operation Alpha Freedom - Feed a Cold



After killing numbers of zombies, the Zombie Helicopter event will be triggered taking off from the hospital before the military barricade.

Duke Nukem
Mission : Operation Bravo Breakout - Desert Rescue



Just before the second fuel station, your targeting laser will turn to green when you are aiming to him. The pilot also mention on that guy when you flew over him. However, you can't pick him up.

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11. Pacifist - Complete all "Escape" missions without killing anyone
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As the description, you need to complete all ESCAPE Mission without killing anything. The mission is as follow:

> Operation Alpha Freedom - A Snowballs Chance
> Operation Bravo Breakout - Bug Out!
> Operation Bravo Breakout - Tank You!
> Operation Bravo Breakout - The Sinking Feeling
> Operation Charlie Takedown - Urban Escape
> Operation Charlie Takedown - Desert Showdown
> Operation Charlie Takedown - Raven's Down

I'm not sure where we can check either certain mission has fulfilled the pacifist requirement or not. I just replay all the escape mission. I've completed the achievement after completing the whole game.

Helpful tips:
Time your boost - use it to evade RPG, Sniper, Jets and Tanks.
Save your fuel - don't take time hovering too long over firing mortar and evading enemy attack.
Remember your route - try to remember the altitude needed by your chopper to maneuver through the terrains and enemies.
Leave the Scoop - you don't have to save Scoop to complete this achievement.

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12. Get the Scoop! - Save Scoop on every level he is present
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Scoop is present on all the mission, rescue them.

To locate scoop, you will notice the big billboard of "2 Scoops of Truth" nearby the reporter.

Zombies DLC mission are not required to complete this achievement.