3 weeks sounds too much optimistic for the first real alpha version even with minimal functionality. Such projects always take more time than we think in the beginning.
It's very important for the developers to plan all future architecture in advance before actual programming. Otherwise you will build a house without a basement and after that will need to repair and repair it each time when adding new functionality.
Other popular conception is to build a simple prototype. Three weeks look real for it. Test it for playability and after that plan and build a new concrete basement for the real game. If there are enough people in a team both tasks can go simultaneously.
There are a number of very high end concepts being shown off here that could take a long time to release, however even if only one of these comes off this could be fantastic.
The first one is the ability for "engineers" to add functionality to their homes such as tic tac toe or simple dice games or just to advertise real life services to all players who visit their area.
The second is the merging of a free to play RPG style game in with a paid building simulation where both games feed into each other. I'm not sure if I've ever seen something like this before in webpage form.
The third is a way to get people interested in crypto currency who would otherwise have never thought twice about it, the market in question being the coders and gamers who have used closed online currencies in game worlds before but haven't made the leap to crypto currencies before.