So, the idea is that there are base raid missions, where the starfield background is replaced for a pretty cliché mettalic base, and there are weapon turrets that shoot you from there, stationed. The weapons won’t do collision damage as they are on the ground (they are shrunk and darkened to denote that), but of course the shots will kill the player, as well as the turret can be destroyed by the player. Too complex/difficult waves would not make too much sense here because of the extra danger of ground turrets (want to prevent highly unfair waves towards the player), or maybe there’s no restriction to them but they are a really high tier mission type.
This mission would behave more like the old arcade shot’em ups where you destroy enemy bases with your spaceship/airplane/winged unicorn and defend yourself from enemy waves, but themed around all the Chicken Invaders universe. Here’s an example of how it could be: