Paper prototype / level design

Let’s paper prototype a game by answering these questions one at a time.
Don’t immediately think in terms of game tropes like “power ups”, “puzzle” or “spikes”.
Let’s only assume an avatar-moving-around mechanic.

Avatar: Who are you?
Sketch it out on a piece of paper, side view or top view, standing or flat.
e.g. An octopus

What makes this character distinctive?
e.g. anthropomorphic but mute

What’s the most obvious and logical setting for this character?
e.g. The ocean

What’s a much more unlikely setting for this character?
e.g. A suburban home

Goals and motivation: What does the character want or need?
e.g. go to the ocean

What’s a less obvious goal/need/motivation?
e.g. raise a human family

Conflict: What’s standing on the way of the goal?
e.g. octopus anatomy

Agency: What’s this character unique way of overcoming obstacles?
e.g. his tentacles

Now build a small world for this scenario. Think of at least:
3 Environments
3 Non Playing Characters
3 Objects
1 Ending

Sketch the elements on the paper an arrange them in a non linear way.

Playtesting

The designer describes the premise to the tester.

The tester moves the character around and describe the action they’d like to perform.

The designer responds to the action in any way that makes sense including “you can’t do that”.
If the action is unexpected but could lead to interesting outcomes, the designer can improvise and add new elements on the fly.

The tester can play multiple times if they feel the possibilities have not been exausted.