Vampire Survivors

Before going for this: you should first obtain the Milky Way Map, a Relic that is uncovered in The Dairy Plant level. This pause menu map will show all items on the map for any level once you get it. Unlocking the Dairy Plant means reaching Level 40 in the Inlaid Library, and Level 20 in the Mad Forest (to unlock Inlaid Library).

With that obtained, you will then need to load Mad Forest and go to the top 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 15-20 minute mark as by then you'd probably selected all of your possible upgrades and may even have evolved a weapon or two.

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 26:16 in the video.