I'm assuming you mean for an engineering position. Depends on both the particular person hiring and the exact job you're looking for. But overall, what I would say is that people are looking for ability. Whatever demonstrates that ability best is what counts. A half working demo mish-mashed together from scratch does not do that. A gorgeous UE based demo mish mashed together from samples and library shaders also does not do that. Apart from that - if I'm hiring someone to be an engine programmer, I expect them to have programmed engines. If I'm hiring someone for higher level logic, game code, etc then that doesn't really matter so much.

For what it's worth, you'll find a lot of advice saying that you have to present something "polished" and in recent times I'm of two minds on that issue. I know a lot more people who really want to see code up on GitHub, see interesting technical work that is well thought out and executed beginning to end, than people who have spent inordinate amounts of time making nice menus and junk.

Also mandatory reading:

• http://www.sloperama.com/advice/lesson12.htm
• http://www.sloperama.com/advice/m86.htm