Sorry for the late reply.
animatist, we are working on improving the controls. Though you have to keep in mind that the nailing is not meant to be possible when you place the planks edge to edge or side by side, but only edge to side, V-shaped. The angle limit is around 160 so you can nail them in pretty obtuse angles though.
Many people have complained about this however. I chose to make it this way because there is no way in real life you can attach two planks like that in real life, you need other tools than a hammer to do that. Maybe it was a bad choice to prevent it just because it isn't possible in real life. I will deeply consider changing this for the next update.
I did try out various methods for antialiasing and spent a lot of time optimizing it. However, the performance cost is too much compared to the graphical improvement.
I came up with another solution by smoothing the meshes and adjusting the contrast, I think it worked out pretty well and it certainly doesn't look as jagged anymore. Check out the latest version!
We have also released a trailer now for those of you who haven't checked out the game it.