I’ve found the “Spot The Difference” pictures on paper to be a fun exercise now and then to use with my Beginning English Language Learner students. They have to find how two similar pictures are different and then, in writing and/or speaking, explain the difference.
There are quite a few of these kinds of games online, but there’s no language development activity really associated with most of them.
However, now I’ve found a nice online game called An Eye For Detail that uses this kind of game strategy, and also provides an English learning opportunity.
Basically it has a bunch of variations on this theme, and the player has to read the instructions each time in order to know what he/she is looking for.
I’ve placed the link on my website under Word and Video Games.