AWESOME! The sounds and visuals pushed this rig to the max!
Demon Attack, in this reviewer's humble opinion, was about one of the smoothest, most-colorful and aurically pleasing titles released on The Little System That Could [sometimes]. In gameplay, it was almost like Imagic's home version of the great arcade game called Phoenix [by Taito, I believe?], but in a simpler setting. The "birds" in these games would swarm left & right and, when shot, they would separate into two smaller "birds". Shooting one of those would cause the remaining smaller bird to swoop down on you, kamikaze-style. Even though Demon Attack was like Phoenix-Lite, Demon Attack arguably had better sounds & graphics than that arcade unit just without Phoenix's pink or lime green planet backgrounds.
The action was fast-paced, the sounds kept you on-edge without annoying you and the graphics were nearly sublime. Although you had a plain black background, the colorful "birds" attacking you were near-psychedelic and the explosions were vibrant as well.
There were many firing options to choose from which would ultimately affect your skill level, but once you split a bird into two, you better have GREAT aim or some guided-missile at your command as one of those birdies will come down to spank you promptly.
A must-have space shooter for the 2600!