This is actually quite nice. Now, I'm just starting out in Spanish, so this is not for me, but I will tell the people who'd care to know what this is. Essentially, this is an English version of the Spanish My Word Coach, with all the spanish changed to English. Okay, maybe that's a bit confusing; let me try again. You know My Word Coach? That game had localized versions, among them, Spanish. Now this is just like what the Spanish version of it would have been, had you gone in and changed all the definitions to English instead of Spanish, but leaving the same vocabulary.
In other words, unlike the first game in the series, this teaches no grammar whatsoever, this is simply a re-tooled version of the Spanish version of My Word Coach. Definately something that could be most beneficial for those who have dabbled in Spanish for a while, but not quite fluent enough to actually use the Spanish version.