Aquapark.io takes the most harmless thing in a summer holiday, a long water slide, and turns it into a contact sport. You and a pack of rivals drop into a twisting tube high above a resort. First to splash down at the bottom wins. Everyone else is something to push out of your way.
It comes from Voodoo, the studio behind Paper.io and Hole.io, and like those games it is built around one easy input with a surprising amount of skill hidden behind it. You only steer left and right. The skill is knowing when to stay inside the slide and when to throw yourself over the edge.

A round of Aquapark.io lasts well under a minute, but the leaders usually win it in one of three ways.
Rivals who are knocked over the edge without a good landing spot fall into the pool and are gone. Come up beside a swimmer just before a sharp bend and push across into them. The bend does most of the work. It also works on you, so watch for swimmers closing in from behind on the inside line.
This is what makes the game. The slide winds back and forth beneath itself, so the fastest route between two points is often a straight line across open air. Leave on the outside of a bend with good speed, glide over the gap, and land on a lower section of the slide several turns ahead. A good jump can carry you from the middle of the pack to first place in one move.
The slow, safe line is fine for learning. If you keep to the middle of the tube and avoid crowds, you will finish most races. But you rarely finish them first, because the swimmers who jump well will pass you overhead.

Most failed jumps fail before you leave the slide. A few habits make the difference:
Winning races and finishing high earns rewards that unlock new swimmer looks. They are cosmetic only and have no effect on speed, so a new player and a veteran race on equal terms. What separates them is how well they read the slide.
Aquapark.io gets a lot right for something this small. Rounds are short enough that losing doesn't sting, there is no menu to wade through between races, and the "fly over the corner" idea gives you an exciting goal every single run. It plays as well on a phone as on a laptop, since the whole game is one drag left or right.
For more quick, fast racing, try Snow Rider 3D for downhill sledding, Slope 3 if you want pure reaction speed, or Paper.io for another Voodoo-style game you can learn in seconds. Otherwise, jump in. The pool is waiting at the bottom.