Style is a method that developers are using to individualize themselves now, to both get a recognizable game, and for genre recognition. You can see this in Helldivers 2, where its physics, graphics, and enemy AI make the gameplay experience super cinematic, while also having realistic human interactions and animation. The style work they put into their music, art and world building make the game's world VERY distinct from other games in the PvE extraction shooter space. Compared this to Vermintide, a Warhammer game in the medieval swords and sorcery style. Also compare it to Deep Rock Galactic as a more light hearted yet dystopian 'having a beer with the boys' while also 'another day slaving away in the coal mine' world, and the available player interactions for interacting with your team mates. These three are in large part, the same game formula, but the style, presentation and user experience are all massively distinct. If you want to see the lengths that developers go to, in order to get their vision's style in place, you can read through the development log that was posted as the game 'Return of the Obra Dinn' was being made. https://forums.tigsource.com/i... - it goes over the 4+ years he was working on the game and the different steps in the process, while working within Unity.

Few things... Game engines provide an easier environment to develop in. It handles a lot of basic things for the developer (renderer, view ports, physics engines, etc) and provides a base level compatibility - generally if an engine is compatible with hardware, most games in that engine should work with none to minimal additional work by the developer. Tracking development from the 80s, the different hardware configurations possible has ballooned like crazy. Most developers don't want to have to do all the development required for compatibility between different hardware setups - each different motherboard/cpu/ram/graphics card combo can have its own quirks and, if developing your own engine from the ground up, could be a pain to troubleshoot -- you either need the hardware in house to troubleshoot on or you need intense logging and the game to crash on that hardware, so that you can get the logs and debug the exact system's issue. Leaning on the engine for this allows them to focus on the game and the experience they want to create, instead of having to devote a massive amount of time and money into specific hardware configuration issues. Also, developers are not always want to create the best graphics ever. Sometimes the style itself is a huge technical challenge and can be a more developmentally rewarding project. In this case, it looks like they were aiming at replicating the cut-paper animation style, similar to South Park's, via the game engine and renderer. From a development standpoint this has quite a lot of challenges all on its own and based on the videos, they did a pretty good job of it.