I downloaded your game and I really like your production values! Everything looks and sounds really nice!
I've had a couple of plays and found the mechanics enjoyable (but hard to get a decent score).
Now, please don't take the following, as criticism on you game, because its not. It's just a general feeling have, about a lot of games on the app store.
I'm an 80's guy and I love old games. I used to play games like Aztec Challenge (super hard) and Hunchback (same) for days! The reason I used to play these games and put up with the difficulty was, that I wanted to know what happens at the end.
Back then, ending cutscenes were kinda limited, but an ending screen was fine with me! Some of the games definitely disappointed me, as they would just loop back to the start.
I REALLY dislike the 'endless runner' genre.
I don't feel any point or drive to keep playing. I guess a lot of people must feel differently, otherwise the likes of 'Flappy' would not have gotten as big.
This is just my feeling on the issue. As far as games go, I really like to be able to work towards 'Completing the game'. Then, if I feel like I want to better my score, I might play it again.
Sorry for going a little bit off your original question, but I just wanted to let you know that you have cool game there, but I would find it way more addictive, if I had something to work towards.
At the end of the day, you should make what YOU love and there will be people out there that will feel the same about it.
I think including an easy + hardcore mode like some of the suggestions above is definitely a good option. Then again, 'Flappy' was insanely hard and most people couldn't score over 10 and yet it still caught on.
One other thing would be, popping up a big replay button as soon as you die