While coding a game, I realized that I was unable to switch screens back and forth. This is a big bug for my game, and I need it fixed if I am going to continue using this app. Please add a block for switching screens.
The recommended method of switching screens in App Inventor
see also tip 1 here
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.
Hello Dmitri
For a game, it would probably be best to use Virtual Screens.
When we define virtual screens, we use one 'real' App Inventor Screen (most often Screen1). Screen-sized Vertical Arrangements on it are displayed/hidden as required - they are the Virtual Screens. This is generally a better approach for multi-screen Apps, they share data without having to "pass" it between screens and it also reduces code duplication, making the App more efficient and the code easier to follow if you have to return to it at a later date.
So, instead of seperate "houses", virtual screens are rooms of the same "house".