Its listed as HL2 SP. The 1 in the corner just means 1 player, just look for the squared sign to see if its HL2.
Also I'd be careful about being self proclaiming about certain aspects- mainly your good architecture comment. Personally it looks like terrible architecture, but good construction (the fact that what you have looks realistic, but that doesn't mean it looks good).
If you want to make it look good you should make the build art deco kinda style. By that I mean sorta georgian period buildings with the nice shallow domes in the cielings with artistic carvings in and decorative trims etc. Derelict/scabby buildings of that style are quite common, and you'll realise it looks better. Max Payne used art deco alot. Heres some images to give you an idea.
I personally suggest playing Max Payne 1 or 2 to get a feel for the style in a derelict stage (if thats what your going for). Using this style is a good way to add alot more detail to your map without too much effort (a few custom textures and a few skirting boards etc).
