The third level is now done. Enjoy the screenshot! Progress on other levels is going well; I expect to finish levels 1 & 2 in a couple of days. Level 6 is the most unfinished level at the moment but also the biggest in the pack.
If anyone knows how to make an Osprey trigger something when it gets destroyed, let me know immediately (the normal "Trigger Condition" method doesn't work)! There should be a way to do this (see Operation Nova, for example).
Not sure how that with the Osprey works but I recommend to decompile the specific map from Operation Nova and see it for yourself.
You can decompile maps with this tool:
Files.thewavelength.net
It is very usefull.. That way I've learned a lot more than in every tutorial out there. I have also received a lot of prefabs from the official Half-Life maps.
But don't use anything created by fans in their custom maps without giving credits to the original author and asking for permission to use the specific thing. Otherwise it would be considered stealing! ;)
Just place the bsp. file on to the exe. file and it starts the decompile process.
I hope I helped you. As side of that fantastic news of course it seems you're making fast progress on your mod.