More info on IGDB

The gameplay is very much like that of the original Xevious except this time it is a little more difficult. Several new enemies have also been introduced (including a silver Galaxian flagship, a rare silver Galaga "scorpion" ship, two jet planes, a helicopter, and a dark yellow Tank Battalion tank). Some of these enemies will reset the player's score back to 0 if they are destroyed - and the hidden "Sol Citadel" towers and Rally-X Special Flags are also located in different places.