At first sight this appears like a fast version of Invaders, but there is a lot more to it than that. The mission objective of the player is to penetrate alien controlled sectors of space, destroying all positions and allowing the Galactic Fleet to occupy the area. The aliens come at you in a similar orientation to Invaders, but not in a similar way. They attack you in a haphazard, random manner from all directions. The galaxy is split up into sectors. You travel through these by way of either (at the discretion of the player) a hyperwarp control or, if you have destroyed all of the aliens in that particular sector, you are automatically taken on to the next one. The first sector is different to the others with eight alien fleets in it which you have to destroy. The following sectors have one fleet in each sector but the sectors get harder to occupy as one progresses, as each sector has a more powerful alien fleet in it. You start the game with four Galactic Empire ships and four units of hyperwarp energy. One of the latter will be dissipated if you go from sector to sector. A bonus Galactic Empire is awarded for each 10,000 points. You also get a bonus ship at the beginning of each sector. You attain further hyperwarp energy for each 10,000 points . . . In the second, third and fourth sectors the aliens are equipped with Photon torpedoes which will destroy you if they hit. After the four sectors the aliens fire torpedoes at different speeds, although the faster they are the smaller the chance is of them destroying you if they hit. A nice touch is that the last three aliens in every fleet are tough little beggars and will stop at nothing to eliminate you.
Delta is supplied on tape but can be transferred to disk without problem. It supports sound of reasonable quality.