Half-Life is one of my most favorite games of all time. It blended action, platforming and story perfectly to be one of the awesome shooters of 1998. But it wasn’t always that way.

Valve, back then a small development studio, made a press demo version of Half-Life that showed a drastically different version of the game: While the story was similar, almost all the levels and designs were different from what we got. Originally slated for November 1997, it missed the release date and came out a year later with many significant changes to the final product, all for the better. Getting a chance to play the Half-Life that never was is really a treat, which has many unfinished levels — some early versions of levels in the final game — as well as tech demos such as skeletal animation. You can shoot a robot and make it do that dancing baby animation that was popular in the late ’90s! Not only that, it has documentation about the game and Valve itself, a walkthrough of all the levels, even copies of Paint Shop Pro and WinZip for some reason…

Here’s me playing through one of the levels, The Security Complex. It’s one of the more complete levels of the game. I go through the stage area at least once, then show the solution as given in the walkthrough.

Thanks reddit user jackaljayzer for uncovering this gem, who got it from a friend in Bellevue, Washington; and to Valve Time (har) for revealing the leak. There’s links in there if you wanna try it yourself. If somehow you are one of the few who have never played Half-Life, go buy the damn game on Steam already.

(The YouTube video is a sneak preview of what’s to come. Stay tuned…)