Hi everyone,
I am working on a top down "endless" space shooter. I wanted to ask what the best way is to create and control waves of enemy's that increase in frequency over time. Here is what i Have:


The created keeps checking to see if the enemies are suppose to be coming <Enemy trigger> then sends x number of waves, determined by a game variable that i increase after each boss battle.
The custom event checks to see if the enemies can be created, and if true, sends them after x amt of time. The issue I am having is after the 3rd boss, the waves are so massive it's completely unbalanced at that point.
I tried using a variable to control the upper number of the random number so the enemies would spawn faster over time, but even if the count got the random to "1 and 1" the frequency of the enemies never changed.
I have been using Stencyl for about 3 weeks now and i'm learning

So any advice and tips on how to accomplish this would be very appreciated.
Here is the link to the game if you want to see what i'm talking about. Note that it starts out slow but picks up after the first boss at 25 points.
http://www.stencyl.com/game/play/14564