It was said to have been developed as a straight-up shooter but the source suggested that it ‘failed’ in that format, before being reigned back towards puzzles and exploration. The source also stated that Half-Life 3 will have a “open-world, quests and NPCs”
The source stated that development is well under way, and that the game will work several RPG elements into the mix. It was also suggested that the game will be a full Half-Life 3, not Half-Life 2: Episode 3.