I've only purchased the starter pack and I feel like the number of ads is once every three of four stages, which I don't have any real problem with. Most seem to be 10-15 seconds in duration and happen just before entering a stage. I haven't minded this especially with the mindset that as I play more and more and see the depth and number of future stages, that getting to Patron level might be a good idea for me specifically. Even before I bought the starter pack, I didn't mind the ad clips because I love the fact that the UI isn't crowded with all sorts of pushes to spend money. This is clearly a premium game experience that is being offered as FTP out of necessity based on modern mobile trends and a lack of a big name IP publisher, so I think it is both prudent and fair. Really hope to see this game get more press and I've advocated to several friends already what a fun and engaging game it is.