When i preview my game it is very transparent how can i fix this here's the screenshot : see attachment I have windows 10 using Buildbox 2
You have the transparency set to 50% ... is to the right of the resolution.. Set it to 100% and you'll be fine.
This I believe a bug i used to have on buildbox and windows 10, A clean reinstall may fix this issue, At least this what i have done to fix it.