Build one playable round first
A prototype does not need a full world, but it needs one complete loop: start, choice, feedback and ending. That loop matters more than asset volume.
Observe real release signals
Once the game is on the web, you can see whether players retry, share or give specific feedback. That signal beats internal guessing.
Choose tools for iteration speed
Early architecture should not slow the experiment. You need to swap rules, prompts and assets quickly while the idea is still forming.