I think that your proposed modifications are headed in the right direction! I have a couple questions:
- How do you plan on making your next level(s) unique and different? What types of obstacles, challenges, and abilities will they include?
- What type of game feedback/juice are you thinking of adding?
- Obstacles and challenges are often included as part of making a level - I'd advise making at least a second level to ensure that you're meeting the criteria for significant modifications, unless you're planning on modifying the tutorial levels.
I'm looking forward to playing your final project!