Multi-unit-select

[corfe83]

Selecting multiple units by means of rectangle or solely one, then targetting an enemy should redirect their attention. The CTRL key with drag/single-select would generate a new rectangle - or select the clicked unit - not overriding the previous. Units remain selected until level completion or clicking air. It permits more advanced actions and maneuvers than the current long press (which obliterates formation). Selected friendly units would radiate the colour aura of your ship; similar applies to the enemy. These features would raise the intuition and complexity of the manual combat system.
All actions mentioned would by completed by left-click, screen drag redesignated to right for intuitiveness. For mobile, you could augment a tab for 'selection mode.'

[ghost]

Additionally, double-click onto a ship would select all of that type.