If it won't play, try renaming the end of the file from .mp4 to .zip or .rar . If it opens as a folder, extract the contents to find the actual video file inside.
Use a free tool like Untrunc or MP4Fix (available on Android). These tools compare the broken file with a working one to rebuild the "install" path of the video data. 4. Check for File Completeness nekopoigobaku021080pmp4 fix install
The "gobaku" part of the string sometimes refers to a split archive (part of a larger set). If the file size is very small (under 10MB), you don't have the full video. If it won't play, try renaming the end of the file from