Before you hit download, ensure your museum-piece hardware can handle it:
The Scratch 2.0 Alpha constantly tried to phone home to MIT servers that no longer exist (specifically the download.scratch.mit.edu API). When it cannot connect, the Alpha often freezes looking for an "update." Disable your WiFi or unplug the ethernet cable before launching the Alpha. This forces the software to boot in full offline mode. Scratch 2.0 Alpha Download
A critical aspect of the Scratch 2.0 Alpha was the offline editor. Because Scratch 2.0 was designed to be web-first, the offline editor was essentially a standalone Flash projector wrapped in a browser-like shell. The Alpha version of the offline editor was notoriously unstable, often crashing if the user attempted complex operations or custom blocks. Before you hit download, ensure your museum-piece hardware