Yes, game jams are really tough with their tight time constraints. Especially when working alone, it's incredibly difficult to get everything done. The only reason I expected a second ending was because it's a huge tradition in these types of adventure 2D horror games. There are usually lots of endings based on the items you have, or things you have to backtrack to. But one ending for a game made in 2-3 days is great. And the animation for that ending was really cool as well, so I liked it a lot. (A chase sequence for true ending would've been insane, though, if you add that post-jam, that's going to be epic.)
Yes, submission errors occur on game jams all the time, apparently this time you were part of the unlucky few whose computers just give up on life 1 hour before the deadline.
About the keyboard: wow, that's really cool. I didn't know the French keyboard was this unique. I can now see why the controls didn't work. It's okay, though, arrow keys work just fine.
One funny thing about the controls, though: I always reach for WASD first, that's how I control games by default. And only D and S worked (I mixed it up in my original comment), so I could only go down and right. So I assumed I'd have to go to the bottom door by default (because I couldn't go anywhere else). When I got there and it said "it's locked" and I was stuck in the corner, I was kind of stunned, thinking "okay, did I just softlock the game somehow?". Then, I realised I could just use the arrow keys and that was kinda funny to me.