Congratulations on your purchase. Looks an interesting bike but well used. I suspect you'll need to invest a bit more money into it before you get the bike at 100%. I would check the bike thoroughly over for all issues. Early versions appear to get stress cracks on many of the components and we are talking about a 20 year old approx aluminium frame here for a bike not known for its reliability or strength and you don't know its history. I'm confused by the design it looks like you would expect the chain to come off when folded unless your bike is missing components that would prevent that. I think considering it's condition I would pretty much rebuild it checking every component as I go and then arrive at a bike at the end I had good knowledge of. You may find the drive components are worn and need replacing especially the chain I suspect. You could just do the minimum and get riding but if you find that your not happy with it then more work will be necessary. What you can't see on an image is the tiny details of hinge play and other worn components. I remember buying a secondhand bike once which on first impressions rode well but then I took it on a ride only to discover at the farthest point away from home a bearing had broken in the front wheel hub and when I got it home the grease inside had pretty much emulsified over the years. I like peace of mind knowing everything has been checked.

I wonder with the suspension front and back if the bike is a good fit for Tannus tyres which are available in 18". Tannus are the solid tyres that never puncture but can give a very slightly harsher ride. Just wonder if its an ideal bike for using them. Not having to worry about punctures or taking tools to deal with them is a fantastic bonus if so.