Four acts
- Act I · First rails — levels 1 to 6: one depot, two to four colors, six then five lives.
- Act II · Building steam — levels 7 to 14: a second depot, then five colors.
- Act III · Under pressure — levels 15 to 22: six, then seven colors, three lives.
- Act IV · Mastery — levels 23 to 30: seven colors, two depots, two lives.
The trains get a little faster and leave a little more often from one level to the next.
Three stars
- One star: Level cleared.
- Two stars: Clean run!, with at most half of the allowed mistakes.
- Three stars: Perfect run!, without a single mistake.
Stars never go down when you replay a level. The home screen counts all your stars, out of 90.
The adaptive final
Level 30 changes with you. Win it cleanly and its target rises; lose it and the target eases off. Its clock follows the target.
Unlocking
Each level opens when you clear the one before. Continue, on the home screen, takes you straight to your next level. See Levels and stars.