Space Echo happens at a city instead of on a lunar landscape, the humans are in a building suspiciously like the Empire State Building (instead of another moon), and alien ships remaining are numbered underneath a big saucer instead of shown waiting for an attack.
blue saucer : 50 points
red saucer : 100 points
Saucer with human : ??? points
Bonus at end of round : 100 points per human not captured