RogueCube (EP)

Beat level 2-3 to unlock this achievement. Due to random map generation, every run is different but example run of the beach levels can be seen starting at 7:46 in the video.

Full video achievement walkthrough:

The beach levels consist of 2-1 2-2 and 2-3.
Be careful of the new spiky enemies on the beach levels, they look purple on the sand, as they can take you by surprise and kill you quickly.
I recommend the explosive crossbow and a shotgun or chaser as they are all overpowered.
Once you’ve completed all 3 levels the achievement will pop.