I'm getting on quite far with my Nuclear Core project but when I try to add the entities trigger_changelevel and trigger_transition to link to the next map, the entities are missing from the list! I have the latest patches. Is the newest FGD the update for 1.0.0.9. That is the one I've just downloaded. About the mod, it is coming along quite nicely! I've built the control room (which has a dead Barney with a shotgun, a dead scientist, and a scared scientist), the HEV room (pretty self-explanatory), the core (which has some aliens in it, and an impressive core) and the transition room which leads to the generator! I will release the first map for testing soon. I put it on last night but it didn't upload properly so I'll put it on again tomorrow probably!
It did have some very bad leaks earlier, so I covered all of the outer surface in solid block and that fixed it!