SE! introduces special custom blocks that let you link and run multiple Scratch projects together. These blocks include:

open ____ .sb3

open ____ .sb3 with data ____

received data (variable)

With them, you can split a large game into smaller projects to avoid memory limits, or create modular designs (for example: a main game, a shop scene, and a cutscene viewer). Because they are technically just modified "My Blocks," you can also use them in normal Scratch, though they will only work as intended inside SE!.

To keep projects organized, it’s recommended to name your main project file and its containing folder the same (e.g., MyGame/MyGame.sb3). The SE! runtime only lists .sb3 files directly inside the scratch-everywhere folder, so additional scenes should be placed in subfolders. A launcher project can then be made that simply runs the main .sb3 file inside a chosen folder. When referencing a project, always write the full path relative to the scratch-everywhere directory (e.g., MyGame/main.sb3).

This feature is especially useful for larger games but may later be replaced with a dedicated extension once extension support is implemented in SE!.