You must enable "Install from Unknown Sources" in your Android security settings to run this file.
Note that saves from older versions (0.2 and below) are generally not compatible with the 0.3 release; players often need to restart from the beginning for all events to trigger correctly. Safety and Security Tips
Most legitimate beta apps (version 0.3) are small – 5–20 MB. A 401 MB APK is extremely rare. Why so large?
: Common in early "0.3" releases where the developer has yet to implement advanced compression algorithms.
If you have already installed this app (or suspect you did):