Thank you, I didn't know there's an offline installer. It worked!
So, while the UI is nice and clean, I did encounter issues that have already been reported here (UI failing to load and being slow when it does).
Other than that, when I tried to change the product's language another error occured. I have attached the log. I think it has to do with an Avast server, the Avast 9 server maybe? Previously, the .2280 version also tried to download the new version from that server and failed to do so.
Furthermore, trying to update the virus definitions also led to an 'unknown error'. Again, it tried to download them from the Avast 9 server. Since I didn't get the option to create a log, I tried to take a screenshot using the Snipping tool. I wasn't able to do that since it behaved really weird with Avast's interface.