It helps a lot to have Artist Cat, as he is cheap, has high health, good DPS, and counters Angels.
Basically, just drop a couple Artists to stall the first few enemies while you build up your money. Then quickly use long-ranged units alongside your Artist Cats.
Try to kill The Angelic Sleipnir quick, as he can do lots of damage.
Eventually, the Angelic Gorys will just stop spawning altogether. Then swarm Sunfish Jones with Artist Cat, and you should win soon.
- This level features only Angel Enemies, just like Red Alert features all Red Enemies, and Black Premonition features all Black Enemies.