First off, if you know anything about Kariosoft you’l know that Game Dev Story orginally came out in 1996 so they essentially copied a game that came out 17 years ago.
and as for “ripping off” parts of the game. The game engine bit is actually ripped off another popular game devlopement sim although I won’t mention it’s name. Game Dev Story isn’t the only game tycoon out there 
What they actually did was just take all the best bits of game development simulators and create a better one and they did a dam good job. Their “create game engine” is far more detailed and indepth and they improve a lot on what kariosoft did.
I’m excited to see what they come up with next.
Also the other game development sim had a stock market feature and throughout the eighties you could invest in game companies, nintendo,sega, ea ect and playing the stock market was fun. I hope they add something like that if they make a sequal.