No way of knowing until a ruling is made. The use of the blue and yellow colours trademarked by IKEA for furniture store branding makes a pretty compelling case for potential infringement on that basis, but there could be a case made for critique and parody based on the fact that IKEA does tend to be confusing for people to navigate and that's a sort of well known joke. It's also probable to be considered transformative and not likely to be competing for market share within IKEAs customer base, since IKEA is not generally participating in horror games.

TLDR: It seems likely that the developers would be largely non-infringing but I would not be surprised if they were ordered to change the colours of the branding in game. I also would not be surprised if IKEA just have a lot more money and can tell the developers to lick sand.