The Harvest for WP7 is one of the highest quality phone games available at the moment. Its classified as an rpg but feels more like a touch screen shooter. It does have a higher price then most of the other games on the phone but I feel it was worth the 6.99$ price.
You play the game as one of three robotic soldiers which each have slightly different abilities that you unlock and upgrade as you play the campaign. You are able to level up and equip items to you character which is where the rpg elements come in. The campaign is roughly about 4hrs long but there is achievements that will require you to put a lot more time into it then that if you want them.
Over all this was one of the most enjoyable games I have played on the phone so far. I would recommend it to any FPS fans who own a windows phone.