This will surely slow down the development of the "flagship", no?
We aim to have it the other way around. Personally, I'd love to quit my main work to be a full-time indie game developer, so that in the future I would have more coding time to help Sami with UnReal World development. After considering various different ways of taking this leap the chosen tactics is a crowdfunding campaign for a small side-game project.
For so many years I have had trouble with finding proper coding time next to my main work. The time has come to ditch my other odd jobs. I do believe that taking this leap will eventually lead to boostin UnReal World development, instead of slowing it down.
EDIT: to clarify; the mentioned side-project is not intended to be a long-term development like UnReal World is. The plan is to spend a few months coding a release version (1.0), then slow down for a few more additional versions (like 1.1 or 1.2), eventually leaving the side-project as it is, so that there will be more time to concentrate on UnReal World development. So, this another game is just a temporary transition phase.
And, as mentioned: an another game could also double as a test environment to develop and to polish algorithms before implementing them in UnReal World. For example, back in the time when I was coding the weather simulation for UrW, I first coded a tiny text-based test environment. I ran hundreds of tests in the sandbox environment so that I got the details of the simulation polished, before the whole thing was implemented in the main game. Now I'm planning a full stand-alone small game, partially for the same reason - to have a sandbox where I can experiment with various algorithms. But this is purely to coder point of view - for the player that mentioned small game would naturally be a fully playable and fully enjoyable game in itself.
Only you, knows what's best for you. And whatever you decide we can do nothing, best of luck with it.
As a customer of UnReal World, I'd much much rather have more updates on that and/or even crowdfound specific features. I don't wanna grap another game to fullfill my UnReal World "needs" and is a little concerned about the state that game could/will be left in (I haven't been here for 28 years, just 2). It does seems counter productive, from a customer's point of view. And I my opinion, there's lots of small stuff to work with in UnReal World already.