I have been practicing Tai-chi since the 1960's and have found it the best exercise for my health. Many people know about the slow movements but there is a lot more to it. There are faster movements and some that are similar to gymnastics (wushu). There are many types of "chi-gung" exercises that range from slow to twisting and rotating movements. There is push hands which is a two person exercise that can be very intricate and fast. And of course there is the self defense (Tai-chi-Chuan) which is the most aerobic exercise I have ever done.
The government of China recognizes around 8 styles of Tai-chi and over 600 styles or systems of chi-gung. It is a vast system of exercise and healing (there is a "Tai-chi Massage") and is worth exploring.