Challenging in a most unusual way. It's difficult to focus on which keys you're supposed to be pressing, and not just reading the interesting text in the thought bubbles. So that mirrors the process of writing quite well - idle thoughts v. pressing keys. ;)
Although I found myself wondering if my keyboard was registering my inputs as the number of thought bubbles increased. I didn't feel like I was always having an impact sometimes, but I could have just been pressing the wrong keys. It ended up being more frustrating than probably intended, though that might be my old laptop's fault.
Chill atmosphere and nice sound effects. Really creative concept. Well done!