The Longing is an experimental indie game by Studio Seufz, and it takes 400 days to complete. While you let that idea sink in, why not watch the game’s latest trailer. Oh, I should warn you it’s a four-hours-long video, so you might want to clear your schedule.

Once you start a new game of The Longing, a countdown of 400 days begins. The countdown is in real-time and continues even when you’re not playing. If you want, you can boot up the game once, and then come back 400 days later to finish it.

You play as a small, pathetic-looking creature called a Shade. Your only task is to wait underground and wake up your master once 400 days have passed. What you do in the meantime is entirely up to you.

You can carve a nice little home for yourself down in the dark where you can sleep, read books, and wait for the days to pass. Or, you can explore the vast underground cave system and maybe eventually escape to the surface.

Along the way, you’ll encounter time-based puzzles, like waiting for moss to grow so it can cushion your fall, or a pool to fill with water so you can swim across. While you wait, you can enjoy the “Atmospheric Dungeon Synth” soundtrack, which admittedly sounds pretty darn good.

The Longing has several endings, and not all of them take 400 days to uncover. But if you do want to see all of them, you might have to actually wait the whole period (or maybe just change the date on your PC? That might work).

The Longing is coming to PC on March 5, and you can already pre-order it off of publisher Application Systems’ website for a 25% discount.

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