Doing anything successfully with time travel, my friends, is like finding your way through a mirror maze using trails of breadcrumbs that you have to lay yourself.
This is a pretty excellent opening / metaphor xD That being said, I feel like the 'my friends' takes a bit away from it. I also think you could extend it just a smidge to make it even better:
Doing anything successfully with time travel is like finding your way through a mirror maze using a trail of breadcrumbs that you lay out for yourself.
And you've been in the maze so long that you're starving to death, so you have to constantly fight not to eat the breadcrumbs, which smell like the best goddamn breadcrumbs you've ever goddamn smelled.
I feel like this line could be cut? Mostly because I don't see its relevance to the metaphor — and because it kind of breaks the pattern for the next bits.
It's like doing a ten-thousand piece jigsaw puzzle where all you have to go on is a blurry photograph of an earlier edition of the puzzle, upside down and half-complete, as seen through a stained-glass window that hasn't been cleaned in months.
This isn't actually that hard? Since jigsaw puzzles are meant to be solved by comparing pieces, anyway (having the original image helps, but isn't necessary). I'd rewrite it a little to be:
It's like doing a ten-thousand piece jigsaw puzzle that depicts a black bear in a black forest at midnight on a starless, moonless, overcast night. And you've got to do it blindfolded.
It's like building a machine, the purpose of which is unclear, using only instructions written in Dutch and a French-to-German translation booklet. Also, one in ten pieces are missing, and one in a hundred pieces are for a different machine entirely.
It's like building a machine using instructions translated from Dutch, to English, to French, to Morse Code — then back to English again. And the translator was drunk. Also, you've got no idea what the machine does, but one in every ten pieces is sapient and wants to kill you.
People never fully retire from the Foundation, not really. They usually know too much to be happy with a life of ignorance, or have been there too long for amnestics to be any use, which grants them a permanent place on the radars of countless other groups. Most opt for contract work — occasional research for an increased salary, or the odd investigation into an extranormal event that doesn't seem to be causing too much trouble. It's for that reason that I found myself standing over a dead body, with a child staring me in the eyes with a look of surprisingly calculated suspicion for one so young.
This paragraph is a mouthful — I'd break it up into two or more paragraphs. Also, I think for that first line to have the impact it deserves, you ought to swap out that comma for a period. IE:
People never fully retire from the Foundation. Not really.
I think my primary issue with this piece is that it's a bit long given what it's going for — I feel like you could have gotten us to where you were going in probably half the text. Still, it was a fun tale that did precisely what it set out to do!