Europa-Park is the core of the resort: more than 100 attractions and shows spread across themed European areas, with major roller coasters, family rides, dark rides, theatres, gardens, and a lot of careful stagecraft. The scale is what makes it work. You can move from a Swiss village to a Greek waterfront to a Croatian coaster plaza in a few minutes, and the park is dense enough that even non-riders have plenty to look at.
The practical rule is simple: arrive before opening, start with the rides you care about most, and leave time for wandering. It is Germany's biggest theme park, and it feels like it on summer weekends.