Hello, thank you for the kind comment and feedback. The red FemSlime only used to spawn naturally when there were only 4 enemies in the level. (to make it feel less empty).
But it was not our intention to have the slime spawn from behind once the remaining enemies were added (Angel and SuccuVick).
Now the Slime only spawns as a mechanic with the trigger plate.
Otherwise we think the level would be a little too cluttered, and we had issues with the "enemy from behind" warning notification if both the FemSlime and DD spawn around the same time.
Hope that answers the confusion!