Twenty

Twenty is a game of skills, focus, and logic that really requires your close attention to win. The gameplay is simple to understand, but actually winning the game requires you to pay full attention to what you're doing.

Before starting you can complete an optional tutorial explaining how the game works. Each level starts with low numbers, from one to three. Your goal is to match blocks with the same numbers and combine them into a single block that will turn into a larger figure by one. For instance, if you match two fours together, you'll get a five, and so on. You have to keep adding them up until you can't make any more combinations.

It sounds simple, but Twenty is actually a hellishly difficult challenge. Match as many numbers as you can and get rid of all the obstacles, and then when the timer runs out, a row of blocks with random numbers appears under you – and you have to keep matching up those. You never really have time to think about possible moves. The higher the numbers you're handling, the more difficult it is to keep getting larger figures. Try the challenge ... if you think you can make it to 20.