Great job, MacBeth! You French folk are so artsy. Right away from reading your introduction, I can see this is gonna be a great hack. Perhaps, for me, the Introduction grabbed my attention and was the most interesting part of your hack. Not so say your screenshots aren't amazing (which they are!), but I'm most impressed by the features you plan to implement, and your overall take on the game's mechanics. I love how you are focused on immersing the player into the story and the difficulty. And dark humour is always a nice touch! :-)
Your sprites, the trainers and Fakemon, are all very well done. The logo is especially also awesome. And the tiles and colours are also very well done. This is a great-looking game.
Lastly, I think I can nitpick the nuances of your hack because it looks like you take it very seriously. My only critique is in the mapping style--it looks to me very chaotic and cluttered. There's SO MUCH going on in every inch of the map that it seems overwhelming, and it also seems like it would hinder the player's exploration. I understand your desire to fill empty spaces and diversify the tiles, but with the small size of GBA maps, less can be more. To add to that, it seems like you didn't utilise the sheer size of your maps (i.e., a lot of your maps are outlined by tons of trees/mountains), so you could have stretched out your buildings so they weren't so tightly compressed to eachother, or to other tiles. For example, a lot of doors have only 1 tile space in front of them; to me, that looks sort of claustrophobic.
With that said, I don't even think that's a big deal. You could say your maps reflect the hectic atmosphere of the game itself, because as you say, you expect "the player to never feel safe in this world." I guess my suggestion is simplify at least A LITTLE BIT. Otherwise...again, great job!!