This game was fantastic.
1) color scheme was good. I have no idea what the other people are complaining about.
2) the dancing flag is a nice touch
3) simple to understand what you need to do
4) starting at the beginning of the stage can be challenging and frustrating, but it is really well-made. Very much like super Mario Brothers. I have rarely seen a game that balances these two things so well.
5) the sliding and jumping against a wall and coming back are very good aspects. Physics was well done for a game -- balance was good of sliding etc. Yet challenging.
6) the only bad things are that the game was quite hard, so expect to get many bad reviews. Only the top 10% or something of gamers will find this to be "not too challenging and frustrating", in my opinion. But I think it is fine! Leave it hard. Just write in the description that it is a challenging game and that only good and persistent players will win.
7) I do think that the stage with the spinning balls was TOO hard, but hey, I did get past it in the end!