Some info on Valve's cancelled projects - Left 4 Dead 3, Half-Life 3, "Valve RPG", and Source Engine 2:
PC Games N -
https://www.pcgamesn.com/half-life-3/cancelled-left-4-dead-3ComicBook.com -
https://comicbook.com/gaming/news/left-4-dead-3-valve-cancelled-details/Info:
- Valve realized they had to re-design Source Engine for the future b/c they wanted to innovate.
- Valve felt they couldn't innovate on that version of the Engine (which was used in HL2: E2).
- So, they began work on Source Engine 2, so they could innovate on future Half-Life games, L4D3, etc.
- Valve was working on 3 projects for the engine: a new RPG, L4D3, and another Half-Life game.
- Half-Life 2: Episode 3 devs began eventually heading off to work on L4D3...
- ...So HL2:E3 wound up eventually fading away, from being worked-on.
- At that time, Valve had a flat corporate structure...
- ...So employees could just jump from project-to-project whenever they felt like it.
- L4D3 was not going to be linear-style L4D co-op based game (L4D1+2 were linear).
- Left 4 Dead 3 was planned to be a co-op style open-world zombie FPS set in Morocco.
- The plan was to have hundreds of zombies on-screen, all before games like World War Z & Days Gone attempted this.
- Half-Life 3 was worked on, which would have some scripted set pieces & some procedurally-generated areas.
- For example, in HL3 - you might enter a building...but the contents inside might be different.
- You might enter the building w/ enemies might be generated & positioned differently by the game.
- Entrances and exits could be in different places, too...for replayability purposes.
- Half-Life: Alyx was at least Valve's SIXTH TIME to try to revive the Half-Life IP since Half-Life 2: Episode 2.
- Valve also was working on a new RPG, influenced by these series: Elder Scrolls, Dark Souls, Monster Hunter, etc.
- Source Engine 2 had issues of no save & restore; no lighting solution; and other problems.
- B/c of issues w/ Source Engine 2, that engine was dumped...
- ...And all of the titles for Source Engine 2 also went with it, winding up cancelled.
- So...HL2:E3, HL3, L4D3, and Valve RPG all wound-up cancelled.