Update: Actual Gameplay!

Some exciting updates, including the first actual mechanic!

• I'm calling the new mechanic forest policy.  Basically, you control how much park staff try to cut unhealthy tress down or plant healthy trees. I started with it more for technical reasons than for design ones: It isn't exactly a central mechanic and I'm not sure how interesting or fun it is yet, but it was simple to get up and running.
  
• A budget window. The design is a work in progress, and I'm not fully happy with it.
• New UI for toggling the visibility of those windows, plus game speed:
  

I'm pretty happy with how all these look, although I'm sure I'll tweak it more over time. For now, I'm going for a flat look roughly inspired by SimFarm and SimCity 2000, which had pretty nondescript windows. It arguably looks more like early 2010s flat design instead of early 90s Uis, especially with the blue (which I plan to swap out) and the icons (Typicons by Stephen Hutchings).

I've been distracted a little bit by technical wanderlust. I've been comparing different game engines and frameworks and trying to get a sense of what I want to use for future projects. C# is a polished and well thought out language and there are tons of resources and information for doing game dev in it. However, I don't really care for the style it's geared toward (OOP via C++ and Java) and getting .NET projects to build correctly is a huge pain. The most promising options seem to be Clojure with LibGDX or Fennel with LÖVE (love2d). Both graphics libraries have been used to ship significant games, but the languages I'd be paring with them are less orthodox. I'd do some testing first and maybe even build a small game.

An honorable mention goes to F#, which I could use with the same libraries I'm using now and could even integrate into Isometric Park, theoretically. The syntax is similar to ML languages' and Haskell's, which would take time to get used to, but I suspect I would like it more than the curly brace style that C# uses.