Here's a simple game with a simple, compelling premise. You are shown two pictures and a collection of letters. You have to guess which word links the two – it comes after the first and before the second – made up from those letters. The eponymous middle word, in fact. The clues, however, can be a little abstract, so it's not as easy as it sounds. There are hints to help you along the way. You can reveal the answer to one of the picture clues if you have enough coins, which can be expensive, or simply remove a letter or two. The hints are limited; you only earn a few coins for each completed puzzle, and start off with 150 coins in your bank. Solving one clue wipes out more than half of your starting stash. So, like other games before it, Middle Words uses the power of social. You can ask friends on Facebook and Twitter to help you solve the puzzle, with fresh eyes offering a new perspective to help solve it. Difficult at times, but addictive.