Firstly, I found many players using the "Very Low" graphics quality which is the default graphics quality before, but they don't know it, then many people said the graphics are too bad in some comments. Although I admit my game graphics quality is not good enough compared with some 3A games, that is not good. To avoid these from happening again, so I changed the default graphics quality to "Ultra" and delete others. Acutally, the "Ultra" quality is just the normal default quality for me in developing this game.
In "Very Low" graphics quality↓↓↓
In "Ultra" graphics quality (should be default normal graphics quality)↓↓↓
We can see there are many differences between 2 qualities, especially texture, blur and shadow.
Secondly, I found many players lost their way in Tutrials, so I made it easier. For example, player only need to buy food from any shops, when player have to buy food from a specific shop in before. I also changed the signal for every resources point.
Thirdly, player can now skip the tutorial by clicking a button on the top-right corner of screen. After player falt by losing any money and resources, I add a statistic interface with total survived days and maximum survived days when showing game over.