Thank you!
Yeah this is a good point, I should have put an hint on the displayed text. On the Main Menu it was only showing the input but I forgot to mention to "hold" the key. (I did mentionned it in the page description)
I'm still trying to figure the best way to enable fullscreen, the way I did here was bad (as we should never force it), got an idea for the next time. I forced it because the current settings i use for unreal don't match itch iframes and makes lot of cuts.
And since it's an unreal engine game, the default fullscreen setting provided by itch wouldn't work as expected.....(Or maybe you just gave me an idea to fix that!)