I'm a forest ecologist / forest health specialist and I enjoy Terra Nil. I'm also a longtime gamer, so I do see some design issues that could make this puzzle game significantly better, but they have done a great job here in general.
Recognize that despite the ecosystem restoration theme of this game, it's basically a puzzle game. The ecology aspect is not terribly strong; nothing like SimLife or Gundan Frontier. But all aspects of the game do have some connection to ecology or ecosystem restoration.
The biggest issues of the game, in my opinion are:
1. One of your final goals is to make all the animal populations happy by creating ideal mixes of adjacent environments. HOWEVER, you don't get info on how good these are until after multiple stages of the game, including AFTER you create the habitats. So you are forced to guess at good habitat placement during the stage where it matters most.
2. Fine tuning environments to give ideal conditions after the animals show up can be really frustrating. Many of your methods for manipulating environments AFTER they have been built are destructive and have significant tradeoffs that can ruin other habitats. Again, the time to make these habitat combinations properly is during the habitat building phase, NOT at the end when everything is already on the board.
3. The encyclopedia gives only vague information on what animals want. Only in game ONCE THEY ARE ALREADY PRESENT do you see the finer details of what they need. The time to have this information available is during the habitat building stage.
4. Replayability isn't very strong, as you create most of the content yourself, so replaying a level doesn't add anything new to the experience. On top of that, there are no technology unlocks so there's no incentive to put additional time into the game. Finally, due to the frustrations above, I just want to call my previous successes good and not re-experience the frustrations.
Ok, so that's alot of criticism, and there's more I could get into, but the overall game is good and it's clear the developers care about this game and the subject. A recent update came out that adds some quality of life improvements and some new dynamics that improve the game (plus new content that I haven't unlocked yet).
Terra Nil is priced appropriately for the quality of its content, and there isn't much else like it. I highly recommend this game, just be prepared for some frustration as noted above.