what did you find difficult about building your…

what did you find difficult about building your project?
what did you find easy about building your project?
what surprises you while building your project?
(liest at least 2 examples)

#1. the logic for coding part, figuring out the big frame logic is not that difficult, but since the project has to do with so much connection and rule settings( for me ).
#2. designing a content, building circuits, mechanic part of project (soldering.gluing)
#3. there are ways of design to make simon says playful.