Here is the full list of all 35 Busway Islands - there are Puzzle achievements.
Complete the 21st island
Complete the 20th island
Complete the 19th island
Complete the 18th island
Complete the 17th island
Complete the 16th island
Complete the 15th island
Complete the 14th island
Complete the 13th island
Complete the 12th island
Complete the 11th island
Complete the 10th island
Complete the 9th island
Complete the 8th island
Complete the 7th island
Complete the 6th island
Complete the 5th island
Complete the 4th island
Complete the 3rd island
Complete the 2nd island
complete the first island
Complete the 22nd island
Complete the 23rd island
Complete the 24th island
Complete the 25th island
Complete the 26th island
Complete the 27th island
Complete the 28th island
Complete the 29th island
Complete the 30th island
Complete the 31st island
Complete the 32nd island
Complete the 33rd island
Complete the 34th island
Complete the 35th island