Harvest beans by hand, then buy potted plants, gardens, farms, offices and factories until the beans harvest themselves. Every building has a flat rate and a flat cost, the prices climb in clean round numbers, and pressing g gives you a hundred beans if you would rather see the top of the tree than work for it.
The author says plainly that they made it hard to build on and dropped it, and that progress does not save because they could not face writing the save code. Both are true. Play it in one sitting or not at all, and treat it as a small honest thing somebody finished rather than a game with a middle and an end.