I just discovered the free game “Narbacular Drop” which is kind of the prototype game for Portal. Gabe Newell, managing director of Valve, took interest in the team’s work and employed the whole staff at Valve. The developers went on to write the critically acclaimed Portal using many of the same concepts.
I have seen some video footage of the game on youtube documentaries and such, but didn’t know it was freely available.
I recall playing this awhile back. It was just alright - I have to give respect to Gabe for recognizing the potential of the core mechanic and its developing team. With the resources Valve provided them, they went from what I would describe as a fairly mediocre project into one of the best games ever made.
BTW many (most? all?) student projects from DigiPen are freely available. Without going into the ethics of it, DigiPen owns the student projects and the creators are not allowed to sell them. Some are on Steam (Steam Developer: DigiPen Institute of Technology). My favorite by far is Perspective on Steam, which blew me away the first time I played it and I still enjoy revisiting it a couple times every year.
I remember playing Narbacular Drop after first playing Portal, it’s interesting but obviously not as refined as its successor but you certainly see the DNA present in the final game. Also if you are interested you can play a game which was the precursor to the paint mechanics of Portal 2 for free