When making something, plan to make it smaller than you even thought possible. If the core is good enough it will be fine - better even - with being smaller. And then you can build from there.
Years ago we had a conversation with a game design celebrity about a game we wanted to make. We loved the idea we had. We had spent so much time in our heads with it, and had everything thought through.
The game would take the player to a variety of locations around the World and involve intricate sceneries. The celebrity designer listened to our pitch. He didn’t comment much on the idea or the gameplay, nor did he go into platforms, sales, marketing and strategy.
“That sounds fun. How can you make it smaller?” he said.
“Why go around the World, when you can go around the block?”
By making the product smaller we increase our chance of not failing. We increase our chance of completing, and then, our chance of succeeding.
We made the game smaller. But not at all small enough. We ended up never shipping it.