Took me a minute to understand what I was trying to do, so referred back to your page to see I was assembling pipes and connecting the circles!! I reckon having that helpful tip in your game initially could help reduce confusion. Once I understood what to do I enjoyed making the circles click into place to form a connected pipe and hearing that great sound choice to communicate I'd succeeded!! While I personally liked the background style, the colour choices may not be the most accessible as I also had a bit of trouble seeing the connection points on the circles!
Overall a fun, functional game that I enjoyed playing through!! :D