Like other roguelikes, the question of how long it'll take you to "beat" Returnal in part comes down to a combination of your personal skill and the luck of the draw. Weapons, upgrades, and health drops are all randomized, as is the map you face on each run and the challenges that might stand in your way. So how long it takes you to hit the credits is going to come down to whether you get a series of solid runs or not and how much difficulty you find in the bullet-hell battles developer Housemarque throws at you.
But there are more caveats to the length of Returnal as well. Though it's not immediately apparent, the game is divided into sections, with some key story developments dividing up the experience. The end of the first section leads to significant changes in the game, creating something of a midpoint from there on out. After the next section, you'll see the credits and an ending cutscene.
However, there's more to uncover in Returnal after that point. So with all those exceptions in mind, here's a rough idea of how long it'll take you to complete each of the big portions of Returnal and how much time you will likely sink into the game.
Altogether, though, to get to the credits, a decent player with some solid runs can probably expect to commit 12-15 hours. You can get there quicker if you avoid exploring and forego searching for audio logs and other story collectibles. Returnal's mapping system is also good about identifying doors that will take you along the path to your goal, as opposed to side rooms that might have extra fights or additional drops in them, if you're looking for other things to avoid to speed up your progress.
To uncover all of Returnal's secrets and find all its story collectibles to get the full picture, you can expect to spend a lot more time in the game. That's partially because some collectibles are locked behind the random, procedurally generated nature of each biome's map, so you'll need to visit them several times to find everything. After the credits roll, expect to push your total count up to 25-35 hours or more, depending on luck, skill, and exploration choices. Let's just say that there's a payoff for the time spent, though.
We've got even more helpful Returnal coverage to keep you alive on Atropos. Check out our big rundown of survival tips and tricks, as well as a guide for opening those pesky orange barrier doors, and our Returnal review. We've also got a piece explaining why you should probably die more and keep your runs shorter in Returnal--the story is better for it.