There's many controversies about Leon Brinkmann aka "SPY", one of the "mapping machines" of Half life and mods.
He is responsible of Leon Mappack, the 6 hour-long Coastline to Atmosphere (a sequel to HL2 not considering Ep 1 and Ep 2), and the infamous Strider Mountain, arguably the longest HL2 mod of all time : you can count more than 12 hours to go through all the levels and collect all datas to open the secret level and true ending.
He said that Final Project Diary would be his last but he was wrong : he is nowadays developing a mod which started as a competition for planetphillip (rooftop ville) and it then goes into a mod called RooftopRetreat... Finally becoming "HL2 Episode 3 The closure".
What is amazing with his mods, and so popular or unpopular, is that he creates massive maps using simple gameplay things, mainly with massive waves of enemies, to pass a point/open a door/etc... So much that during the buggy/car parts, it would be faster on feet than on car!!!
Anyway, here it is : Moddb.com
Prepare yourself to fight 10,000 Overwatch soldiers, 50,000 Antlions, 100,000 Manhacks, and probably 1,000,000 headcrabs!!! Surely you'll die of exhaustion before the end, but... you know it, Leon's style :) !!!