CRACKME.EXE

There's a man who won't wake up, a yacht you can't afford, and a code you haven't been given. The programs seem quite happy to leave things that way.
You'll have to interfere.
CRACKME.EXE is a hard hacking puzzle game where you mess with the actual files and programs behind each challenge. You'll leave the game window and use real tools to investigate how they work. Finding something useful in a file is a start, but the fun is figuring out how to use it to make the damn thing cooperate.
The opening challenges help you get started. You'll need to do some reading and learn unfamiliar tools as you go, and some of your ideas will go nowhere. Later challenges expect you to choose your own approach and put several things you've learned together.
I made this for people who open a game's files out of curiosity and end up spending the evening there. Experience with CTFs or reverse engineering will help. If you're new to this, expect to spend a fair amount of time looking things up.
The full game is planned to have 24 challenges, with hints available for the first 14 only.
All targets are programs and files supplied or created by the game on your own computer. The external tools you’ll need are free, but you’ll have to download them separately.