I got really far down and the only way down was through a hole with colourful lights and a safe floor at the bottom, i took my chance and sailed through the floor like a ghost floor, had to start all over again because a game bug. I am guessing others have experienced this.
On the plus side i like this game better than Only Up, which i played a week before hand. I find the 3d effect in Only Down bit more fun and the different shapes to walk and run on and land on better, where as Only Up all you have are pipes to jump on, except when you reach the train station