The game had a very sharp difficulty curve, but in kind of a bad way. It was very tough to get started and to get a decent colony going, but once you did you could snowball through the rest of the yard. I could take on giant spiders and harvest food from them, and of course any other colony.
I shudder at imagining a lot of the earlier Sim* games without a manual and largely pre-web. Without the space or time to create digital help content, there was so much that was only mentioned in the manuals!
I remember the SimEarth one being a pretty hefty tome.