I am pretty sure that's what i made it for as well :) I wish you luck with the acheivements :D

It's cool, don't worry about it. As I played on, I sort of realized that it's the game's fault. I couldn't custom search any other map either. I'm trying to complete the 99 achievement fast now so I'm looking for levels like this.

Yeah i wasn't able to find it either in the custom search and i had to manually close the game to get out of it. I don't really like the interface in Chucks Challenge and find it really slow to load on my connection and havent played much of it, but my appologies that your not able to get to the level.

Pretty sure i didn't even put that ID there :S

Can't find this using 16845. Are you sure that is the correct ID?