Hello, thank you for the feedback!
1. 2. Are you running on a recent/latest version of Sound Show? what is your OS (windows, mac, linux)? Those issues should not happen. Maybe contact me trough the contact form on my site so that I can further investigate https://www.soundshow.app/contactus
3. In the recent version, there is an aspect ratio option in the edit popup of the videos. But you are right that it cannot be changed once playing. I'll add that to my todo list.
What do you mean by "tiled manner"? Is it being able to play multiple video on the same screen and setting their position/size?
4. I have not noticed such issue. Maybe you could share a video so that I see/hear the issue.