Think you're good at observation?
Here's a lovely (said sarcastically with a little snicker) game wherein you attempt to find the "change" or error in picture in a certain amount of time. People are added or they disappear, shadows are added, words may change, birds and clouds come and go. The changes can be incredibly subtle, and many take several attempts to find the change. It's particularly addiciting, I'm noticing, because there aren't any clues. You either find the change and move on or you keep replaying the same picture. The only hint provided is in the error message, but because it's a translated from Japanese site, sometimes the message only obfuscates the change even more. Yet I can't stay away.
The green bar on the right shows the time you have to beat. And it goes very quickly.