Coin runners is basically battle mode except that you do not have balloons, instead you try to collect coins. Getting hit causes you to lose three coins, so even if you make it to the maximum score of ten coins, the battle isn't over until the time is up.
As I stated above, online play has been improved greatly. The new communities feature allows you to create your own community to play with your friends whenever they're online. In the community settings, before you "publish" it, you can set what game mode members will be playing and what items will be used. You also name the group and can put up a two to four word message that members can see, then you can share your community code with your friends or anyone else you want to invite to your group, even if you've just 'met' them online. Unfortunately, there are a lot of options that would have made this feature better that are not present, but hey, no other Mario Kart has communities at all!
Now to look at new items. There are three new items, replacing some of the older ones. The new additions to your arsenal are fireflower, tanooki tail and lucky 7. The fire flower allows you to hurl fireballs at your opponents forward and backward, and they ricochet. Awesome, right? I think so, but there's a catch, once activated, it will disappear after a little bit, probably between ten and twenty seconds if you don't shoot, but if you start spraying them all over your opposition, it will only let you launch about ten fireballs. All the same, I think this is my favorite of the new items. I've hit up to three opposing karts with one flower, once you've mastered fire wielding, you'll be delighted to see this botanical wonder pop up in your item box.
The tanooki tail is the same tail Mario used in Super Mario 3 and, much more recently, in Super Mario 3D Land. It is used to block shells from hitting you, knocking away banana peels and even opponents! It, too, is only useable for a limited amount of time, but if used timely, can be a devastating weapon.
The lucky 7 is the most unique item used in Mario Kart yet, when activated, you get seven random items that rotate around your Kart. I discovered that you can choose what you're using by hitting the "L" shoulder button when the item you want is directly in front of your character. I heard that if someone bumps into you while your weapons eclipse you, they will steal some of your items, so watch out!