Getting this achievement can seem like a challenge, especially since there’s no way to see which items you still need. The good news is that even if you haven’t examined any items you can unlock this achievement in less than 15 minutes using only three levels. This guide will also get you the achievements It's just basic chemistry, yo and Master stacker if you haven’t gotten them already.

Copying this list into a word document is a nice way to keep track of items as you go

Guns:
• Dlaser-93s
• Dmp
• Fixed Butterfly
• Handgun
• Killer6
• Nk-13
• Riotgun
• Rocket Launcher
• Shotgun

Ammo:
• Hg Ammo
• Mg Ammo
• Mp Ammo
• Rf Ammo
• Sg Ammo

Gun Powders:
• Blue Gun Powder
• Green Gun Powder
• Red Gun Powder

Smoke Grenades:
• Green Smoke Grenade
• Red Smoke Grenade
• Yellow Smoke Grenade

Herbs and Herb Vials:
• Green Herb
• Red Herb
• Yellow Herb
• Herbs Vial (G + G)
• Herbs Vial (G + R)
• Herbs Vial (G + Y)
• Herbs Vial (R + Y)
• Herbs Vial (G + G + G)
• Herbs Vial (G + R + Y)

Other Healing Items:
• Brown Egg
• First Aid Spray
• Sardine

Damage Causing Items:
• Green Egg
• Sardine (rotten)

Chances are very good you’re missing Herbs Vial (G+G+G) as you can only craft this in one level and making it isn’t part of the solution. Go to level 40 and combine two Green Herbs together to make Herbs Vial (G+G) (I suggest examining this vial as it's another easliy missed one), then combine that with a third Green Herb and examine the resulting Herbs Vial (G+G+G). If this isn’t the item you’re missing continue to the next section starting at the level reset.

• Start at Level 40

• Combine two Green Herbs and examine Herbs Vial (G+G)

• Combine Herbs Vial (G+G) with a Green Herb and examine Herbs Vial (G+G+G)

• Reset the level

• Examine each Gun (DMP, Handgun, Killer6, Nk-13, Riotgun, and Rocket Launcher)

• Examine each Gun Powder (Blue, Green, and Red)

• Examine each Herb (Green, Red, and Yellow)

• Examine the Brown Egg and Green Egg

• Examine the Red Smoke Grenade and Yellow Smoke Grenade

• Combine one Green Herb with a Red Herb, one Green Herb with a Yellow Herb, and one Red Herb with a Yellow Herb and examine the three vials (Herb Vials G+R, G+Y, and R+Y, respectively)

• Combine Herbs Vial (G+Y) with A Red Herb and examine Herbs Vial (G+R+Y)

• Combine two Blue Powders, two Green Powders, and two Red Powders

• Combine one Blue Powder a with Green Powder, and one Red Powder with a Green Powder

• Examine each of the resulting ammo types (Ammo MP, SG, HG, RF, and MG, respectively)

• Go to Level 38

• Examine the Shotgun, Dlaser-93s, Fixed Butterfly, Sardine, and Sardine (Rotten)

• Go to Level 37

• Examine the Green Smoke Grenade and First Aid Spray

• Congrats, you’ve unlock one of the rarest achievements in the game

Thanks for checking out my guide. Did I get something wrong or misspell something? Let me know in the comments.