Took me a little bit to figure out by myself that you press E to select new recruits at the end of a wave and switch between them on the fly during gameplay. With how fast the enemies move across the screen (and they move VERY fast), it's difficult to keep both of them alive at once. I do like the concept of different people with different roles defending a ship though and the controls are decent enough even if the weapons themselves have limited range. Maybe if the overall pacing were slower and focused on protecting the ship as well as the occupants, the idea of controlling them individually at a moments notice would be more manageable imo