and dota 2 is on a modified source engine, which is used by portal 2, which is used by half life 2.
You are the most hopeless fanboy I have ever seen, lol.
Except Valve never advertised it as being a different engine, dipstuff.
stuffty level design is always a relevant argument
that was more towards black ops II, but I have no reason to believe ghosts will have levels that are any better.