A lot of people including myself have had trouble completing cubes because things wont render such as the slices. I have had problems where i couldn’t see what i need to fix because only the default texture was there(the checkerboard texture). This kind of server lag really makes it difficult for everyone to play and should be fixed, might i recommend having the necessary picture files download to cache and delete for every cube. This kind of system would lessen server load and stop the annoying “lag”. Please for the love of science fix this soon. 
Hi steigs333,
We’re sorry that we are having so much difficulty supporting all this enthusiasm. We’re working on it and hope to make everything better soon.