The Outer Worlds

"Hard Time" will be earned at the beginning of the final story mission. The game will let you know beforehand that once you arrive on Tartarus there's no going back so make sure to save before traveling there if you're still missing any achievements you can get in your playthrough. :)

This achievement is unlocked when you land on Tartarus. It is story related and unmissable but there are two different paths to get there. The conclusion of the main quest, Kept Secret but not Forgotten provides us with a branch. The easier way is to choose to skip the Hope directly to Tartarus. This is the Path of Halcyon associated with the 'bad' ending. If, however, you choose to skip the Hope to Terra 2; you must find a Tartarus NavKey before you can land on the planet. This is the Phineas Path associated with the 'good' ending.

If you choose the Phineas Path, go to Phineas's lab. Hack the terminal to find he's hidden something in a secret panel. In the inner section of the lab, you'll find the Tartarus NavKey. You can now select Tartarus as the destination.

Regardless of which path you take, the game will warn you that going to Tartarus is a point of no return and creates a system save file. You can choose defer going to Tartarus until you finish your business elsewhere in Halcyon. Whether or not you go immediately or prefer to do other activities first, when you arrive on Tartarus, the achievement pops. You will advance the story to its end. Once you finish the game, you can use the system save file the game created just before the arrival on Tartarus to do mop-up activities and/or play the DLCs.