Flattered that you include my game Hover Car Race Challenge Accepted! on a list of AGK's "best and biggest" but it really isn't, it doesn't even come close to Tobias_Ripper's orignal question. It's pretty one note and a bit too difficult from what some people have told me. However, I did finish it and you can download it from IndieDB and Google Play, links in my signature.
Out of the other games mentioned, I have played Rush to Adventure, which I'd say comes pretty close to being a "large game", and Eat Drink Slay, which doesn't have any narrative structure but is more than a mini game. I also believe that it wasn't finished but it was still enjoyable in its unfinished state.
Like DavidAGK, I'm also working on
rogue machine which is probably the biggest game I've ever attempted.
Like others, I think it's very possible to make a big game in AppGameKit with lots of game play and other things going on. It really just needs someone to put the effort in.