I'm so sorry about this - and angry at me for not re-checking I had the right version on time while I still had 2 hours ahead of me. Lesson taught and learnt.
I've made a list of people's advice and I'm planning to work on it to improve things a bit again tomorrow, so if you want to add some advice or things you'd like to see in the game feel free to make a list too ^^ Dialogue things noted, the other bugs don't exist anymore in the version I thought I'd uploaded.
The invisible character thing and freeze was due to the level being instantiated a second time after dialogue closed, without freeing the previous instance. It was easy to solve but yeah, shitty bug sorry again !