Vampire Survivors

Before going for this: you first should obtain the Milky Way Map, a Relic that is uncovered in this very level. This pause menu map will show all items on the map for any level once you get it.

With that obtained, you could then proceed to the bottom right area where a coffin logo is pointing to. Once you get there, you will be greeted with a circular group of enemies that pulsate around the coffin, you MUST destroy each of the enemies before you can open the coffin. Due to their relatively high HP, I highly suggest leveling up a bit before you get to the coffin. From personal experience: the best time to make it to the coffin is right around the 20 minute mark as by then you've selected all of your possible upgrades and may even have evolved a 2-3 weapons. This area was somewhat difficult to get to in my experience since the addition of all the walls resulted in me getting corned quite a few times on the way over so ensure that you take your time when needed and backtrack if necessary to thin the hordes.

Regardless of what you do, just ensure that you have enough time to get there AND defeat the circle of enemies before the grim reaper shows up at the 30 minute mark to avoid any sudden deaths.

Here is my Full Achievement Walkthrough where I show where to get every achievement in Vampire Survivors. This particular achievement appears at 17:59 in the video.