Quite good. Physics not as good as original Mario Kart, notably missing jump gliding, and generally not as sharp! But it is OK.
Some of the weapons are too useless that you are just better firing them straight away at wall immediately to get something better, they could have a little better balancing there. I'm talking about you gatling that takes 10 seconds to finish firing, and does not kill enemies immediately. You are better off just firing that gun immediately when you get it to be able to get another gun ASAP.