Rescuing Sparkles the Unicorn, again

So, get this: after getting Sparkles the Unicorn out of trouble last year, I was looking forward to visiting her this year. I'm sure you can imagine my shock when she wasn't home: when I got to her house, there was a note taped to her door. Now my pleasant visit turned into a rescue mission!

/visit-sparkles

The first stage of the puzzle is at /visit-sparkles.

BPM CVQKWZV UCAB ZMUIQV NZMM

AMJH OCZ XJMMPKODIB DIAGPZIXZ

WN BPM KWUXCBMZ.

FVB?

HP OZ YZE MPWTPGP JZF.

JR QB ABG ORYVRIR LBHE YVRF.

RZ YJ IJO WZGDZQZ TJPM OZMMDWGZ XDMXPDOMT.

UVY KV DL ILSPLCL FVB HYL VYNHUPJ PU UHABYL.

EM PIDM BISMV GWCZ CVQKWZV.

MNIFYH MJULEFYM ZLIG NBYCL BIGY.

XKGJ UAX TUZK, ROTK HE ROTK.

LHJO SPUL, H SLAALY. MYVT AOLT, H SVJHAPVU.

DGLB SQ. RUM UMPBQ, MLC NJYAC.

ACZGP ESLE JZF LCP SFXLY.

Each line is encoded using a Caesar cipher with a different amount of rotation for each line. I worked out each line and what the letter offset is (using CyberChef):

Each offset represents a letter of the alphabet. Taking the nth letter of the alphabet for each offset, n, gives rersomesrftsbo. That can be unscrambled to the phrase "somber fortress" (thanks anagram finder website!).

/somber-fortress

(or /fortress-somber, the order doesn't matter)

Here we get the next stage of the puzzle.

You arrive at the gate to a large, ancient fortress. The air is cold, and the stone walls are a dismal grey. You can see Sparkles beyond the gate, trapped once again. Sparkles sees you, and rushes towards the gate. The gate, however, holds firm.

On the wall next to the gate is an alphanumeric keypad with a small note taped to it. You're concerned for a moment that someone wrote the access code on the note. That'd be very > poor security! But no, thankfully it just says /##£.

In front of you is a pressure plate, and a large leather knapsack sitting atop it. The bag is empty. You push the bag to the side, and stand on the plate. Glowing letters appear in the surface of the obsidian wall. They read:

SURELY A COMPUTER COULD NEVER SOLVE SUCH A PROBLEM.

THE WEIGHT’S THE KEY, YOU SEE.

AND COMPUTERS WEIGH NOTHING.

Seven stones fall from the ceiling around you, crashing into the floor below. You narrowly dodge these stones, and the dust takes a moment to settle.

Once the dust clears, you can see that the stones vary in their weights and sizes. On each stone is printed a set of letters. Each stone also fills the bag a specific amount. Thinking quickly, you pull your notepad out, and form the following table:

% of bag filled	Text on the stone
12%	ONTMCR
18%	MLRKAP
27%	EDJCSH
32%	LKQJZO
54%	CBHAQF
74%	UTZSIX
86%	QPVOET

The proper way to solve this

All of the texts on the stones are the word POUNDS with different amount of letter rotations:

The offset value is treated as the weight of the stone in pounds for this puzzle.

Here's what we need to figure out: we need to fill up our knapsack with stones to make it as heavy as possible, keeping in mind that we can't overfill the bag. This is a form of knapsack problem.

The optimal solution is to put the 2 pound and 25 pound stones in our bag. Combined they take up 98% of our bag and weigh 27 pounds.

The puzzle text says that we need to enter a code into "an alphanumeric keypad", so we know the next URL to go to is all digits. Since the sticky note says /##£ (£ is the currency symbol for British pounds), we know to get to /27 next.

The cheaty way to solve this

Just try all numbers from 0-100. I wrote a script to try all possible numbers, but it wouldn't be to hard to do this manually.

/27

The final stage is a quiz with 10 random questions. Here are all possible questions and answers: