Board Thread:Questions and Answers/@comment-33320918-20171026134736/@comment-26692787-20171026215933

All old materials are used for extensions up to level 1200 and to build some nice buildings with a low ratio for incredible amounts of material. The new HL materials, which unbalance IMO the game, are only used for Christopher and Ling, and to increase your population to enormous amounts. After building all extensions there will only be left one group of achievements Determination at level 1700. And you are right, at this point not much is left to do. You can try, if not already done,
 * to complete ALL achievements
 * maximize all your contractor's stations
 * complete your museum
 * help new Players
 * or quit, for some time or complete, as many of my friends at these levels did during this year.