you can use 2D barcodes like QR codes as trigger points for mobile guides and games. the app you make doesn’t really care what is stored in each barcode, just that they are all unique. so my suggestion is to make the barcodes all point to a description and download page for your app, so if someone scans it with their phone, they are prompted to download the app and join in the fun.
to make your 2D barcodes unique while all pointing to the same web page, you can use anchor links e.g. #anchor at the end of most urls. as long as these anchors don’t exist on the page, the link will work, but won’t vary.
the example barcodes here is taken from the qr code scanner in the app furnace online editor.