Summary
A focused prototype tests the player experience before the team commits to a large production. Build one core loop, observe players, and use what you learn to decide what to improve next.
1. Define the core loop
Describe what the player does repeatedly and why that action is satisfying. In a platformer, the loop might be moving, jumping past an obstacle, and reaching a checkpoint. Pick one question to test, such as whether jumping feels responsive or a challenge is readable.
Build only enough of the surrounding game to answer that question. Placeholder art and simple interfaces are useful when they keep attention on the interaction.
2. Watch people play
Invite people who have not seen the prototype and give them a goal without explaining every control. Observe where they hesitate, what they try, and whether they want another attempt. Ask open questions afterward instead of leading them toward the answer you expect.
Keep notes on patterns across players. A single comment can reveal a useful idea, but repeated difficulties are a stronger signal to investigate.
3. Iterate with a purpose
Choose the most important problem, change one or two things, and test again. Keep a short record of the hypothesis, the change, and the outcome so decisions remain grounded in evidence.
Once the core interaction works consistently, add a small vertical slice to test how art, audio, progression, and technical constraints come together.