Why do I only see one option to choose from?
When you see an item for the first time, Semper assumes you do not know it and shows the correct option only. The next puzzle for that item will have two options, the correct solution and one that is usually fairly obviously incorrect. The number of options and the difficulty level will increase as you solve puzzles correctly (and decrease should you solve them incorrectly). Similarly, the frequency with which you see puzzles for an item will decrease as you learn it.