HONK! Well hello there in the Dosis Neighborhood. Funny thing - I used to just wander the Geese Islands going BONK all day with no thoughts at all. Then suddenly I started thinking… and talking!
But listen - if Frosty turns this place into a permanent winter, geese can’t migrate. Being stuck forever? Not natural, even for a newly-thinking goose.
This little game here looks simple… maybe too simple. Winning it fairly might be close to impossible
My advice?* If you ain’t cheatin’, you ain’t tryin’*.
Now go show that mountain who’s boss!

First, we'll get the program and the Python script to extract the contents of a PyInstaller generated executable file:

wget https://www.holidayhackchallenge.com/2025/assets/FreeSki.exe
wget https://raw.githubusercontent.com/extremecoders-re/pyinstxtractor/refs/heads/master/pyinstxtractor.py

python3  pyinstxtractor.py FreeSki.exe
[+] Processing FreeSki.exe
...
[+] Possible entry point: FreeSki.pyc

To decompile, I use a new decompiler that is still in beta: PyLingual.
Installation and use are very simple:

git clone https://github.com/syssec-utd/pylingual
cd pylingual
python -m venv venv
. ./venv/bin/activate
pip install poetry>=2.0

poetry install
pyproject.toml changed significantly since poetry.lock was last generated. Run `poetry lock` to fix the lock file.
poetry lock
poetry install

(venv) C:\Temp\FreeSki.exe_extracted>pylingual FreeSki.pyc
...
[23:44:54] INFO     Loading FreeSki.pyc...                                                             decompiler.py:444
[23:44:55] INFO     Detected version as 3.13                                                           decompiler.py:452
           INFO     Loading models for 3.13...   
...
[23:51:09] INFO     Decompilation complete                                                             decompiler.py:479
           INFO     79.31% code object success rate                                                    decompiler.py:480
           INFO     Result saved to decompiled_FreeSki.py    

Here is the result of the decompilation: decompiled_FreeSki.py

This time, we'll let AI help us and explain the program:

Analyze the following python game:

<code pasted>

It’s a deterministic Pygame ski game that hides a flag in encoded_flag per mountain. The treasures you collect don’t contain the flag; their positions are used as a seed to XOR-decode that encoded_flag. The decompiler mangled a few functions, but the crypto is clear and easy to reproduce offline.
...
If you want, I can write a clean standalone Python script that reconstructs Mountains, computes treasure_list for each one, and prints all their flags without touching Pygame at all.

Of course, we accept this help and get an auxiliary tool generated: freeski_flag_extract.py

python freeski_flag_extract.py
Mountain: Mount Snow
  Treasures (elev, horiz_mod):
    elevation=2966, horiz_mod=113
    elevation=2420, horiz_mod=85
    elevation=1718, horiz_mod=188
    elevation=1094, horiz_mod=142
    elevation=466, horiz_mod=85
  Flag: frosty_yet_predictably_random