I am starting a countdown to spawn enemies for my personal S.I. after 80% of the previous wave's enemies have been defeated. I will have 4 different types of enemies. I need an algorithm to procedural generate which enemies get spawned in which rounds. I am thinking of creating a formula to spawn the enemies (all four types) in this format...
numRounds = batsSpawned (the easiest enemy that only follows the player)
(numRounds - 5)/2= cannonsSpawned (projectile enmies
(numRounds - 5)/3 = plugs (shoot electricity between eachother thus they will be spawned in 2s)
(numRounds - 5)/5 = enemy balls (moves in fast circles)