The game starts out at a very simple level, but soon gets quite tricky. One of the particular difficulties is when the compound noun has a totally separate meaning from the smaller words that make it up. A fairly good knowledge of common English words certainly helps, although it can be played entirely by trial-and-error too, for those who may have a smaller vocabulary. It also needs a pretty good short-term memory, and a little lateral thinking sometimes. (The vine structure is pre-defined when the level starts, so you sometimes have to figure out how to re-orient all your word links to make them fit).

From a gaming perspective, the concept is nice and easy to learn, and the interface is very responsive. The graphics are moderately simple, but very effective. I believe all the levels in the game (with the possible exception of the beginner levels) are randomly generated, so it is replayable, and you couldn't cheat by stealing somebody else's answers!

It is a good game, and I reckon it could make quite an effective casual addition to English learning, whether by native or foreign speakers.