The amount that they spawn is based on the time loop. In the tutorial, I suggest "do every 0.1 seconds", but if you want to lower the amount, increase the time between spawning. For example to spawn half as fast, use 0.2 to double the time between spawns.
It's a rather large game, and I made it before understanding some tricks to keep the size down. If your computer or internet is slower, it may take some time to load :(
 "Stencyl Tutorial: First Game")
 "The Lonely Square")
 "TDP4 Team Battle")
If you mean "bad" guy, Tutorial 3 of Set 2 goes over some basic AI coding.