I would like to see an option in the menu to disable the confirm on downgrade. Once I get far enough, I like to disable old items wood just so I can place vendors elsewhere. An option to disable the confirm would make all those downgrades easier. BTW I like the idea of disabling old items that don't produce much income.
When re-assigning, I would like to click and drag unused derps with working ones without having to open up the small menu. Some times I forget which group I'm looking at, and end up assigning someone to the wrong task.
While I like the idea of non-stop waves, I think it should be a separate toggle from the speed. I switch between fast and slow speed too often, and now I have to press the button a second time.
It would be nice if I didn't have to click again to buy fuel after selecting a destination. Would I really want to say no? Just auto buy and save me the extra click.
The "Remember what I'm creating" doesn't always go back. If you tell it to make water, which requires air, which requires light, it will jump from water to light, then stay at light without going back to air or water. Also a problem if creating something that has 2 different materials. If trying to create tree, will jump to soil to create that, but without water it can't jump back to tree so it stays at soil.
I would like to be able to hold down the mouse button on an upgrade, and it keeps upgrading until I can't afford it. This saves us from constantly clicking.
What do you mean by invisible walls? Was it on the roller coaster track?