This is the format that games are created in. Games you create yourself should be saved with an extension of ".asl".
This is the "compiled" version of the ASL, which will hide the code of your game from anybody who looks at the file, making it very difficult to cheat by looking inside it. ASL files can be converted to CAS files by using the QCompile utility.
These are files saved to your hard disk when you play games and save them, in order to finish them some other time.
These are compressed files which can contain one or more other files. Quest can open ZIP files directly, and play a game contained within one in ASL or CAS format. It can also read any graphics or sounds contained within the ZIP file.