It's a wonderful game, it's simple and very easy to understand (And I definitely didn't find this through Folioscope, cough cough) I have a few suggestions if you're struggling for ideas.
1. Power ups, perhaps (speed boost, higher jumps, etc.)
2. Different balls do different things (double points, +10 to score after you die, slower or higher speed, etc.)
3. Phantom spikes / holes. They disappear as you get close to them which may make you jump on another spike
That's all! I wish you luck! So far it's awesome.