The final achievement is titled "another second in the game" and didn't unlock for me on my first playthrough. Here are the steps I took to unlock it, and tell me in the comments if you know another way that worked for you.

1. Go to the settings menu in the top left of the game
2. Click "reset game"
3. Click (or use an autoclicker) until you unlock the achievement. It happened for me around 1600.
- Don't use upgrades in the shop, as they do nothing to speed up the process, and may possibly ruin your chances of getting the achievement.

This is my first guide (and it's super short) so if there's anything I can improve tell me in the comments.