Glad to see you again

Well, I already solved some problems and now I have a pretty good 45 A¬? diagonal platforms collision detection.
Anyway, what I said in my last message is that I use 2 different methods for collision (for collsions between sprites I use a DelphiX/Omega function, hope you know this libraries). But I made my own method for platform collision. And I explained how I do this in the second point of my last message. I only wanted to know if it is a good way of doing it.

Now I'm wondering how to "create" the enemy sprites. Create all of them at the begining of the level? or create them as they appear on the screen?