Alright, I'm back :D The game has improved nicely, good job. Giving the player the power to change the speed was a great choice.
Some things that I felt could be added/improved are
- Speed gauge. It's clear that the speed changes but I'd like to know how much. Or maybe you could just add "Speed: 1/2/3" to the UI.
- In level 3, at 800 m, there's a spinner I couldn't pass at all.
- Level 5 was very difficult, even more difficult than level 6. But I finished it, it was fun! Swapping the levels' names around should be enough.
- The challenges were too hard for me unfortunately. Well, they wouldn't be challenges if they were easier I guess. They are too long, though. 1000 m is plenty.
- Some obstacles shake or fall down in the later levels. They don't impact gameplay negatively so no biggie.
- I'd like that you put back the objective text to the normal levels. It's in the challenge levels so why not in the normal ones?