I'm on a stable wifi connection and I'm on an Acer Aspire 5. I tried a restart and encountered the same issue.
Unfortunately, we could not reproduce the issue :(
Probably it is caused by high quality sprites that we use in the game and some machines with integrated Video Card has lack of memory to correctly work with them through WEB version.
Could you please give a try to the downloadable version of the game?
Some people who had faced this issue told us that there were no issues when they run PC build.