Conduct a usability test.
Use the Usability test FIgma template: https://www.figma.com/community/file/980390517073913918
Just use the template for Task 1.
Find someone who will be your game tester. Think of a task that they should complete in your game. Then take notes. Do not intervene. Finally, ask them questions on what they like and dislike
User: Sakeena
Task: Get to the end of the level.
Liked: How high the character jumped felt natural.
Disliked: Jump distance was too short.