Hello Lenjuni330,
Any luck still?
If the advice supermoskus didn't work you can try follow this method.
Go to the Itch homepage and download the Itch app,
THEN, download the Raft through the Itch app!
Voila! You should be able to launch the game!!!
I actually downloaded the "actual" file first, since it was right in front of me, having no luck; but after I used the advice above, I was able to play it!
Good luck!