I think it is best to say two things right up front : firstly, The Spoils is a collectable card game just like Magic the Gathering . If you are not familiar with this form of gaming the rest of this review is going to be impenetrable, but in short each player builds a deck of cards from a much larger pool and then plays this against the opponent's deck. Different cards have different effects, the skill in deck building lies in picking cards that compliment each other. The collectable part comes from the method of acquiring these cards, instead of just buying a full set you typically purchase small packs containing a random selection of cards, so each player is building decks from a different subset. Vast secondary markets exist for players wanting to trade surplus cards with others, sometimes for surprising sums of money since some card are deliberately printed in small numbers.
Secondly 
, The Spoils is a collectable card game just like Magic the Gathering. Seriously, it is basically Magic with a quick paint job and the VIN ground off. This is not necessarily a bad thing - I like Magic the Gathering, but the similarities are pretty blatant. I can almost imagine playing a Spoils deck against a Magic deck in the same game, most of the rules work in exactly the same way, only with different keywords (cards don't get tapped, they become "depleted", etc.)
Having 
said that, Spoils does differ in a few interesting ways which seem to be designed to make the decks play more consistently. A common problem with Magic is that sometimes you just don't draw enough land cards of the correct type to play your hand full of spells. In The Spoils, you start the game with two staple resources (basic land) cards of your choice already in play - this hugely helps if you are running a 2 colour deck since you can ensure that you have both colours available.
Additionally, the costs for all cards are colourless - you can tap (sorry, deplete) any colour to pay for them. However, most cards have a "threshold". A certain character (creature) might have a threshold of 3 rage (red) with a cost of 4 - to put this creature into play you must deplete 4 resources (of any colour) but you can only do so if you have at least 3 red resources out (depleted or not). Along with the staple resources there are special resource cards that still produce a single mana but count for double when calculating threshold, as a special bonus the card art for these special resources features scantily clad ladies for no particular reason.
You 
can play any card in your hand as a resource by playing it face down. These work just like regular resources but do not count towards threshold at all. Although you can usually only play a single resource a turn, you can deplete 3 resources to put another resource into play at any time.
Combat works much the same as it does in Magic, the big difference is that characters have an extra Speed statistic. This works much the same as first strike but with multiple levels, the faster character hits first and suffers no damage if it kills the other character outright.
These changes do make for a smooth game - it is almost impossible to imagine getting screwed by a bad starting hand in Spoils (especially since the mulligan rule is very forgiving.) On the other hand, one of the things I like about Magic is the unpredictability that forces you to have backup options in your deck if you don't get what you want, Spoils is more forgiving but I think less flavourful. You could get much the same effect in Magic with a couple of house rules.
The card design is good without being brilliant, the art is perfectly OK if sometimes a little tacky. It may seem like I am damning The Spoils with faint praise, but there is actually a lot to like. It is just that The Spoils has little reason to exist in a world that already contains Magic the Gathering.