It's quite common to make constant adjustments to various aspects of a game during its development. Sometimes, level design needs to be altered, and other times, animations may not be satisfactory and require rework.

Here are some reasons why such adjustments are frequently necessary:

1. Tester Feedback: Opinions and feedback from testers, whether internal to the development team or external, can provide valuable insights. If certain levels are confusing or frustrating, or if animations don't achieve the desired effect, it's important to respond to that feedback.
2. Balancing: The difficulty and balancing of a game are crucial to the enjoyment of players. If certain levels are too easy or too difficult, they may need adjustments to ensure an optimal gaming experience.
3. Aesthetics and Immersion: Animations play a key role in creating immersion and an engaging game world. If animations aren't smooth or don't achieve the desired visual impact, a revision may be necessary to meet aesthetic goals.
4. Technical Constraints: Developers may encounter technical constraints or unexpected issues during the implementation process. In such cases, adjustments are often unavoidable to ensure technical feasibility.
5. Development Process: The development process is often iterative. New ideas may arise, and the team may discover better solutions for certain aspects of the game during development. It's crucial to be flexible and make changes to deliver the best possible player experience.