I've now played the 0.3 version several times. I really like it even though it feels quite challenging after the first version and I still don't get all the things affecting happiness. But hey, colonizing a new planet is not fun. :D
One annoying bug to fix in the future versions: When terraforming is selected, you have to be extra carefull NOT to have some building construction selected at the same time. If you click to do the terraform you might end up building something by mistake even if you thought you were about to do terraforming.
Improvement suggestion: When selecting a terraform piece, deselect all building pieces currently selected and vice versa to prevent accidental construction.
I've done this mistake by accident myself several times now.
Thanks for the feedback! I'll fix the bug that you mentioned in the next small update. Also, what in your opinion was too hard during gameplay? Was it the number of available free workers, limited amount of some resources, or maybe something else? I'm asking because I want to make a little shift in game balance, to make the game a little easier, but to do so I need more feedback on specific rough gameplay parts.
Most often I seem to get into this chain reaction: happiness is getting low and I start to lose people (or not getting enough of them) which leads to everything failing OR to increase happiness enough I need to use quite a lot of resources to cover the building costs. I tend to start running out of food at some point. Often it takes most time to get enough fertile soil for farms, depending on the map of course.
However, it's also possible that I haven't learned the right balance yet...
To my opinion, the costs of buildings is a lot more balanced now than in the previous version.
PS: I've been only playing on "normal" mode.
I analysed my difficulties more and noticed that the negative happiness spiral is always the following:
1) Happiness is going doing.
2) Raising happiness would require buildings which need a high number of people (parks and restaurants).
3) Because of the happiness level, I can't get enough people to join my colony to raise the happiness.
4) Happiness keeps going down which is the end OR I ran out of food because farms also require people.
Improvement suggestion: Adding a building option to improve happiness which doesn't require people at all.