Steam Half-Life is a bit above 1.1.1.0, isn't it? 1.1.1.0 is the latest WON version.Will change, no need for version for Steam-HL anyways. ;p
Switching to topdown mode should be as simple as placing a trigger_set_camera, selecting Topdown from the Camera Mode dropdown menu and triggering it. (Using a trigger_once or multiple, trigger_auto's won't work) It's possible it's more bugged up then I thought (It doesn't work to switch back to Platform mode :S), so it's been completely rewritten for RC2.
The other way to switch to topdown mode is entering "hl2d_camera 1 255" in the console. That always works afaik. ("hl2d_camera 0 255" switches back to platform)
In other news: There will be a Flat-Life christmas mappack in the next couple o' days, accompanied by RC2.