

While I love the thought, what makes Portal the best game is GLaDOS, and the story. Solving the problems quickly took back seat to the GLaDOS interactions and story; I don’t think I’d enjoy a dungeon crawler version of Portal nearly as much without her, and the story.
It’s a big part of why I don’t like MMORGS and combat royals, where it just feels like random characters sprinting everywhere in their own little worlds and no cohesive story. I get why many people do like it, and it’s obvious why studios love the format - they’re just low cost money printers. To each their own!
I’ve done the Arch to Artix. It wasn’t hard, per se, but it took a while. I think that should be Medium, because Artix isn’t just an Arch derivative.
In fact, might I suggest a different way of looking at the difficulties?
And so on. You get 1 point for Easy, 2 for Medium, 4 for Hard, and 8 for Extreme. Add 'em up, go for a high score.
I don’t think rolling your own is that hard, TBH, unless you’re expected to also build a package manager. If maintaining it would be harder than building it.