Thank you very much for your comments!
(1) It would be great if a native english speaker could look over the dialogues (I'm actually a french-speaker). Do you have an address where I could send them?
(2) Yeah, I implemented a check: if the player pressed on any of the movement keys for more than 0.4 sec while in spellcasting mode, the character goes out of spellcasting mode... The issue with the WATER spell is that both W and A are movements keys. Hum, I guess I'll have to add some extra checks in the new version to cancel the countdown to 0.4 if you switch keys.
(3) The "ESC + no quit" only sends you back to the beginning of the current scene (So you don't have to restart the whole game). I added this mechanics to get a way for the player the restart a level if he somehow gets stuck (....I had a bad accident ingame with a sarcophagus lid once)