To start off, I wanted to point out that the latest few builds have been performing exceptionally well. As I was playing recently, I thought of 3 specific modifications that might work well.
1. When building long walls or fences, we should have the option to extend the width of 'squares' that we want the fence to cover. I can picture this being done by simply clicking where you want the fence to start, and dragging it to the endpoint. If this is not possible, maybe give the option to manually enter the numeric value of squares for the fence to cover?
2. During night-time mode, park lamps should light up the surrounding area to an extent. Think RCT3.
3. The 'black abyss' surrounding the park should be customizable. For example, making it appear as a sky with clouds might be a cool idea and it could make the game feel less, depressing, if you will.
Just my 2 cents. Keep up the great work! This project is phenomenal.