Agreed. Scrollbar would be good - some TODO for the next polishing jam! As of now you have to click on the left level (6 in the screenshot) to "scroll" left and on the right(8) to scroll right. I purposely hide the levels not yet unlocked - maybe also change that, yes.
And unfortunately it's just 8 levels. However, I have to say it again: Achievements are one big fun part of the game. The game's core loop it optimized around the fun to deliver the passengers and repeating a level is actually not bad - particularly with hunting the achievements.
