Based on the user reviews of the app "Core Ball - Insert Needle" on the Apple App Store, here are three cons and pros in 15 words or less for each: **Cons:** 1. Users find the app's instructions unclear and confusing to follow. 2. Some users report issues with the app crashing or freezing. 3. The app's limited functionality is seen as a disappointment by some users. **Pros:** 1. Users praise the app's interactive 3D model for helping with needle insertion. 2. Many users find the app's detailed tutorials and guides helpful for beginners. 3. Users appreciate the app's real-time feedback and correction features.