Rushmore Waterslide was a good set of slides. There were 6 true slides, a tube ride and some stuff for little kids. The main area featured 4 slides that were all pretty descent; adjacent to that were two more that ran the length of the hill with a few bumps in them. They were identical and gave the same thrilling ride. I'm no rookie at watersliding and can get more speed up than most and it was easy to get air on the two Banzai slides. It was a lot of fun but hard on an old man.
The park was at least a few decades old and it would have been awesome when it was new and the joints of their slides aligned; fortunately, the management knows that no one wants to rip their backs apart on poor waterslide joints and there are plenty of mats available to keep you in one piece.
The tube ride was okay but its age and feeble attempts at repair made me wonder how safe it was. You routinely got caught in ebbs that prevented your progress; they even had one staff member posted part way down to get you through the most troublesome spot. At other spots, they had made holes in the sides of the slide to put ropes through so you could pull yourself out of the back-current. These holes were not made very cleanly and the rough edges could have easily hurt someone. Also, they'd added height in some places using wood with metal plates to hold it together. This had obviously been done some time ago and left jagged edges and loose nails all over. I didn't have any problems or see anyone who did but it certainly was a bit unexpected in a country world-renowned for frivolous law suits.
The park policy concerning weather was a bit disappointing. They shut down the slides at the sight of lightening. This wouldn't be unreasonable if the park wasn't on a huge hill where you can see 50km (30 miles) away. We sat waiting for the park to reopen when it was obvious to most of the adults there that the storm generating the lightening was easily going to miss us by a dozen miles. At one point they even advised us to seek shelter as the storm was about to hit; it didn't even sprinkle.
They later shut the park for good because of the weather. Fortunately for us, their policy of "no refunds or rain checks" was not enforced and we were invited to keep our wrist bands on and return on another night for free during their twilight hours. About an hour after we left, there was a bit of a light shower so I guess they weren't completely out to lunch on their forecast.
Oh, one more weird thing: when we arrived, the staff advised us that they reserve the right to close if they don't get enough people. There would be no refund if that happened. That policy seemed to me to be counter-productive as it would potentially drive people away who would have otherwise paid to stay.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.