Feedback & what to communicate to the players
Show what you got
Add basic feedback early
It is highly recommended that you include basic feedback for the main mechanics of your game as early as you can in your prototype. Polished feedback takes time to create, but having none at all can get in the way when you try to validate that a mechanic works. For a first version, you can use a simple shift in color, a camera shake or any other simple tool you already have.
Feedback helps players understand the result of an action and its consequences, even without final assets.
Example: If you create a platformer where you can get hit by spikes, add feedback for the hit. Make the character blink red, for example, so everyone can understand what just happened.
What to communicate
Giving feedback on everything in your game will muddle everyone’s understanding of it. Focus instead on a few critical elements first.
Ask yourself: “does the player need this information? If so, what can they do with it?”. If the answers fit with the core of your experience, you probably need to communicate it in some way!
Not everything should be on the UI. Diegetic effects (sound effects, visual effects, animations, etc.) are just as effective, and they keep your UI easy to read and uncluttered.