Conclusion

With Aer, Aqua, and Terra solved, the answers can now be combined.
Combining aerQ.png and mareliberum.png gives a QRcode, which scans to themothmisleadsme.

Thus using thecathurtsme as the username and themothmisleadsme as the password, /centrum/ can be accessed, which reveals that the final answer for the weekly is andthesableyedothinjureme.

And this, is this end for the weekly.

Extra Terra

This is one of the few pictures from the first verion of the weekly that ended up not being used in the puzzle.
The picture depicts an ouroboros with the part where the head bites the tail highlighted. This is a hint to taking the "heads" and "tails" of the words featured in the picture.
Doing this gives terrasirradientpng, which terrasirradient.png was supposed to give 1/4 of a QRcode in the first version.

Easter eggs

I had plans of adding secret levels at /uranus/ and /neptunus/, but I didn't have enough time to design 2 new levels. However one of them might become the new 2023 vos bio puzzle.
The only easter eggs that I managed to add are 4 words in Codex Arcanum, which they are:

69 - unfunny

420 - unfunny

666 - eee22

1984 - literally

That really is all for the eggs.

The first version, and the gibberish answer

The first version of the weekly contained 11 parts: 7 planets and 4 elements. All of the levels that the are in the current version are from the first version, while I never managed to make an Ignis for the first version.

unused original intro image

One of the ideas that I didn't use was based around the Library of Babel.

There would've been 5 text files in the library, with one of them being Codex Arcanum. The other 4 files would've been solved linearly, and at the end it would lead to a page from the Library of Babel.
This also ties to a question that you might have had:

Why is the answer for mercurius gibberish?

It has to do with XOR. There is NO easy way to get 7 answers that have to:

- be actual English words
- make sense (not word salad)
- fit the overall atmosphere

And thus I had to cheese the method by forcing the answer with a gibberish string. This was originally planned to be the answer for the library level, with the page telling you very specifically that it is indeed the answer already.
However I could not make this work with how much time I've spent bruting for a potential answer, as well as the fact that HTML maps break easily. I never got the map on that library to work.
And this is why the answer for Mercurius is a gibberish string - I had to make it gibberish to get thecathurtsme.