Considering the pain-points in your review, I honestly think that maybe this type of game just isn't for you - there really is no mid or end-game to these games. You can self-impose challenges, try getting achievements, but there isn't a point where you "complete" a map, or the game. It's all about the casual and chill playing.

It's not finished though? As you start building elements into what feels like approaching the mid-game, there's nothing more to do/build. The community mods, that add building upgrades/levels and new elements into the game, help a game session run a bit longer. Because there's little to no diversity a second run through isn't enticing.

If there was something between thumbs up and thumbs down, I'd choose that, but ultimately I'm left feeling dissapointed when I'm done with the game...

Well, it was made by 1 (one) developer 6 years ago. If you loved the game, also praising it's vibe and soundtrack, but still leave a negative review, because it's not longer being worked on, despite being finished - then shame on you. There's a difference between not adding additional content to an already finished game, and abandoning a game. The only thing that is disappointing is your apparent entitlement.