It is useful to be able to place objects using scripting, for example to load levels from files, and so create compound objects made from various components. This tutorial describes a basic setup for this. It includes a PDF and an example blend file. The written tutorial assumes programming knowledge, but you might still benefit from the code in the example blend file.
Excellent work as usual, Herman. I don’t think the slow building of the level is that big of a problem, since the curtain could be used to your advantage. Why not turn it into a loading screen? This would be very easy to do if you could simply get the number of objects that need to be loaded and keep a running counter as they are being added. Run a simple calculation to find the percentage, then just combine it with goldentaiji’s healthbar tutorial to make a functional and accurate progressive loading screen.