Following the trend of Simpsons games parodying many gameplay styles, this one parodies GTA. Not in the same sense as in things like weapons being present or true open world, but in freedom to travel each stage with a vehicle or on foot, collectibles to find, side quests, and story missions.
Yes, I did say stages. It isn't truly open world. There are three stages that are different parts of Springfield, each one basically one long track that loops back to connect with itself: The residential areas and the power plant, Downtown Springfield, and a part of Springfield I'm not sure how to classify, like the docks, Springfield Dam, the observatory, the Duff Brewery, Kamp Krusty, places like that. The game alternates between these three stages for 7 levels, alternating time of day, the characters you play as, and in some cases adding new paths, changing others, and opening new places to look at.
Overall it is a wonderful game. The humour is on-point and there are gags and references aplenty. I will say, and this is something I think many who have played this game can relate to, the final missions of the game are ball-bustingly hard. I to date have never finished the last mission and regardless of how many times I revisit the game and attempt it I may never will. It is insanely difficult. Aside from that, the game is great and certainly worth your time.