Half life 2 playable instantly on steam now? no dl or install needed whats going on?

whats going on guys?

newly formated pc, new windows 7 install and steam install and i click to download hl2 and its instantly ready. no download time required just...done.

i load it up and it runs. what in gods name is going on, is steam streaming it now? am i just geting old, is this what the internet is now, all instantaneous and sparkly?

no not steaming it, i can play it in offline mode... this is some sick rick and morty shizzle

Halflife 2 isn't that big a download, depending on your connection it can be downloaded in minutes.

no man im talking instantaneously, click to install. does the initialization for a few seconds then boom ready maybe 30 secs tops

oh right, its cause i had HL source installed so the engine and a copy of the game file for hl2 is actually carried in the download of that game.

interesting

this: https://steamcommunity.com/app/280/discussions/0/357288572132126429/