The file format of LiveCode scripts is a binary, at the end of the binary there is a checksum in order to verify file integrity.
However the code part of the script (i.e. what you type in the script editor) is mantained as is. So as last chance you can recover your work using a text editor. Opening it with a text editor will show you something like that:
However you should open LiveCode script just with LiveCode, as opening it with a text editor will corrupt the file so you cannot open it in LiveCode, so if you need to do this always work on a copy of your file.
This plugin that make backups automatically could be safe your works: http://livecodeshare.runrev.com/stack/799/Auto-backups
Scripts only stacksEdit
Version 8 of livecode introduced a script only stack. This type of script has all the code in the stack and has no graphic. The file format is pure text, like:
script "test1" put "hello world"
However you can't create a standalone from a script only stack, at the present it's just a prototype feature. If you need a script only stack use the procedure described in this page: Run only in shell script mode