Oh yes, I had the same disappointment, only they asked me to buy the full game half an hour after I started playing it. I even wrote them an angry letter telling them not to treat their customers like that anymore, and now I ignore this developer. I really like APKInvision https://apkinvision.com/ in this regard, as all the games there are free and full-size. I was especially impressed that I found Soul Knight there, which is an excellent analogue of Hollow Knight: Silksong, I think you've heard of it. In general, for me it was a great mobile adventure.