Promesa

Located on the fifth level (if you're using Scene Selection, otherwise it's the level where you begin walking down a narrow alley) Begin by going down the stairs and through the door to your left. Go through the adjacent door and follow the hallway down through the next door and take a right. As you walk through the narrow alley, look at the first window sill to your right to find a juice box. The achievement will unlock right away and I HIGHLY recommend finishing the level instead of quitting out. When I quit out my Scene Selection option vanished. Luckily I was able to quit out and reload the game to make it appear, but you do NOT want to risk another playthrough of this game.

The fruit juice can be found on 5th level using stage select (Thumbnail is of an alleyway) on a windowsill to your right halfway through the level while walking down the alleyway.

I show the location in my Achievement Walkthrough starting at 3:40 in the video.

After beating the game you unlock stage select.
On the 5th stage there's a fruit juice box you need to look at for an achievement

See in video at 5:15
Achievement Walkthrough: