requires knowing how to code
As a programmer, I wouldn't say this game would require too much knowledge to code. "Angry birds tutorial Unity" is a googlable thing and while not for absolute newbies, this kind of game is not very hard to make. The problems will start when integrating art with the game, unless the art comes in "absolutely game-ready state" which is never the case. Scalability problem will come later when the game gets extended with features, and IMHO it's the problem that kills most projects (maybe this one too?) and highlights difference between an experienced dev and an aspiring one: it doesn't require much knowledge and skill to start up, especially if there are fancy pictures/animations to show, but adding more features turns the code into unmaintainable mess.
Also don't forget that Maskopatol explicitly asked not to put copies of his work anywhere online. So, using his art in a new game is not an option either even if it can be extracted in some state readable in other engines / I see standard texture atlases, but not animation curves. And even if it's possible, then not too reasonable, because it will block how far the game could be extended by the existing art, and as already noted above, keeping the artstyle is also quite complicated.
Yes, this is the reason why "(free and) open source" concept exists
So that the projects won't die even with author no longer able to contribute it in any way.
And in the end if one actually makes a "new game" with "new art"... it's just a new game.
And with the amount of attention (e.g. comments/year or positive reviews on this forum) this game gets in comparison to an average VN/idler...