[...] Chapter 1 is finished and the content I add I hope you like it. [...]
The latest bugfix solves the text problem - now it's readable in every scene. A minor remark would be to hide the text box in the scenes where there's no text, but that can be fixed sometime later as it doesn't break the gameplay.
Overall the game seems to be running smoother, however the lag issue still persists. It usually starts around the moment when sister catches MC with his pants down and becomes worse from there.
My guess would be that it's an issue in the script as if some assets get loaded (e.g. background music) and don't get closed so they stack up and it becomes a memory issue.
Other than that the content looks good and interesting enough to play further. I'll get back to it once the problem is resolved.