After giving out some keys on keymailer, I saw that several people on youtube have made a review or done some kind of playthrough. As a developer, it's interesting to watch people play your game for the first time. Anyway, I noticed that most people never found out that Charlie can actually dive into the water and they miss about half of the game that way. So I added a little message at one place in the first level saying that Charlie can dive into the water.
Also some people were experiencing problems with controllers where Charlie was moving or kept moving. I now made the analog controllers less sensitive, so hopefully that fixes it.