jai's author, Jonathan Blow, always creates a game from scratch. His games: Braid (highest rated XBox Live title when released, "Xbox Live Arcade Game of the Ye

jai's author, Jonathan Blow, always creates a game from scratch. His games: Braid (highest rated XBox Live title when released, "Xbox Live Arcade Game of the Year", https://www.youtube.com/watch?v=YgGeBOC0PX4 https://www.youtube.com/watch?v=YgGeBOC0PX4) and Witness (while not winning significant awards, regularly appears in Best of Decade games lists, https://www.youtube.com/watch?v=URjb3RBIe7c https://www.youtube.com/watch?v=URjb3RBIe7c). Besides that there are multiple games where people use their own engines: - Possibly among some of the most technically complex ones are Factorio (e.g. https://www.youtube.com/watch?v=zRYQcVb_5W0 https://www.youtube.com/watch?v=zRYQcVb_5W0) and Noita (where every single pixel in the humongous world is simulated https://www.youtube.com/watch?v=prXuyMCgbTc https://www.youtube.com/watch?v=prXuyMCgbTc) - Among the AAA-level crowd there's Decima (Death Stranding https://www.youtube.com/watch?v=tCI396HyhbQ https://www.youtube.com/watch?v=tCI396HyhbQ and Horizon Zero Dawn https://www.youtube.com/watch?v=u4-FCsiF5x4 https://www.youtube.com/watch?v=u4-FCsiF5x4) and REDEngine (Witcher 3 https://www.youtube.com/watch?v=YdHc3JZixRY https://www.youtube.com/watch?v=YdHc3JZixRY, Cyberpunk 2077 https://www.youtube.com/watch?v=BO8lX3hDU30 https://www.youtube.com/watch?v=BO8lX3hDU30) - There are smaller ones like Monkey X (Crypt of the Necrodancer, https://www.youtube.com/watch?v=u_avgU1u6yM https://www.youtube.com/watch?v=u_avgU1u6yM) - There are bigger ones like Clausewitz (basically all of Paradox Interactive's games like Crusader Kings https://www.youtube.com/watch?v=0M9qKVCl6HQ https://www.youtube.com/watch?v=0M9qKVCl6HQ and Stellaris https://www.youtube.com/watch?v=eoAkomMEFQo https://www.youtube.com/watch?v=eoAkomMEFQo) In general, once you know what you're doing it sometimes pays to develop your own engine that is specific to what you're doing. Unity and Unreal are generalist enines that you still to bend to your will to do what you need to do and may have opinionated setups of things that are hard to work around, or maybe are omitted from the engine, or just plain don't allow you to do.