Only skimmed the other posts:

Most of these errors or problems or bugs are none of the above. You can't just create any old level you want and expect it work in 3DGS or any engine efficiently. There are rules of level design and certain ways that specific tasks are done and creating levels and those tasks based on these rules and protocols will help insure a smooth or smoother running level and more pleasant experience.

Also, reading the manual, reading the current tutorials, and exploring the forum for advice is going to help out immensely as well. I've been creating fairly complex levels for years, and I have few problems, bugs, hiccups, etc. I'd like a few specific features which I post in The Future from time to time, but sometimes they can be a bit on the esoteric or specialized side, and I don't expect Conitec to come to my rescue any time soon. I hope they do eventually, but there's always helpful, friendly, and willing programmers around here that might help out if they feel like it (or if they like the color of your money ).