Progress Update (Now Day 5)
Day 4 was spent fixing the inventory and equipment system, and getting farming to work. You can now till soft soil, plant seeds in tilled soil, and use a watering can to keep the soil wet. Each day, the plants grow a little bit and the water dries up, requiring you to water the plants again. Right now alternative sources of water are not available (e.g., rivers or rain) but that's not hard to put in. I might do that on Day 6 if there's time.
There is a day-night cycle (how the plants grow) and seasons change, but there's no observable differences in these yet. Combat is also there, but rather basic and enemies don't have a good enough AI to fight back.
Today the plan is to expand the content. Add some more plants, enemies, populate the dungeons, and make the plants do something. I'll be adding villagers as well. This should continue into Day 6, so that by the end of Day 6 I'll have all the necessary content for the game to be finished. That gives me Day 7 to fix bugs, clean up the UI, and call it done. Even if I was to end the challenge tonight, I'd still call this a success. It's far more finished than my attempt last year, which didn't even get off the ground. More screenshots will come tonight, when there is something significantly different from the pics above.