Thanks for the hint jensj12 and sorry for the late reply, looks like only 1 post per day for the newbies directly after the first one.
To answer you questions, although it is already solved, I installed OpenRCT2 via the OpenSuSE package manager, YAST, and I saw the four buttons plus exit and options but no demo park in the background. With the JSON issue in mind I downloaded OpenRCT2 from the website and did some sleuthing.
After comparing the Data directories from the download and my installed version it looks like the object directory is missing in it's entirety, which of course is where all the JSON object files are stored. Copying over said directory to where it should be in my installed version got everything working.
I have submitted a bug on the OpenSuSE bugzilla, #1120400, so if anyone else has this issue on OpenSuSE they can help to push to have the problem fixed.