No, 4GB is just for the 4 games that get directly downloaded through the emulator itself. For the full set of Laserdisc games the emulator supports the total filesize is much bigger.

Don't forget that these games are using streaming video from laserdiscs originally. Daphne get around this by having a copy of the laserdisc videos stored as MPEG2 files that it uses instead of a real laserdisc. These video files are very big, hence the size of the downloads.