Well disclaimers don't actually mean anything to anyone. It is worth ruining some of your good levels to get customers. If someone plays the game, loves it, and wishes they hadn't had a couple of levels spoiled for them - thats a win for you (and for them mostly, they probably wouldn't have played it otherwise).
Also I just played "This Is The Only Level" as per waxpancake's comment. It's a fun flash game, but it still seemed fairly disposable. The thing your game has all over it is the graphics - but you haven't really given it any character - your dragon and princess don't say anything. A bit of humour and characterization goes a very long way in fun little iphone games.
Character is important! In Plants vs. Zombies there's that crazy guy named Dave who sells upgrades and says ridiculous things. Each plant and zombie has a distinct personality you can read about that's fun and goofy. There's visual jokes as well. And the end-game music video is an awesomely silly reward for all your time spent playing. All of this adds up to an experience people feel connected to.
Also I just played "This Is The Only Level" as per waxpancake's comment. It's a fun flash game, but it still seemed fairly disposable. The thing your game has all over it is the graphics - but you haven't really given it any character - your dragon and princess don't say anything. A bit of humour and characterization goes a very long way in fun little iphone games.