Locomalito does all of his games (Maldita Castilla, Hydorah/Super Hydorah, L'Abbaye des Mortes, etc.) on his own. His only collaborator is Gryzor87, who does the music.
Thomas Happ did Axiom Verge on his own, as I recall. [Ah, already mentioned, I see.]
If you go back to the 80s, virtually all games were made by a single person, or at least small teams. All Atari 2600 games were made by one, maybe two people. Same with 8-bit computer games. Seems like as you got into games requiring more intense graphics and storytelling elements, the need for a team of artists, writers, composers, and programmers to make it all work increased.
Post edited April 17, 2023 by andysheets1975