This is an introductory level, easier than the others, containing a single extra ball. The others each have two extra balls apart from the last level. You can only accrue a maximum of 5 lives, though you still get the points bonus for claiming the extra ball if you already have 5 lives.
There are a number of hoops to jump through, literally. This is the objective of each level - to find all the hoops and jump through, or in some cases into or on, before the exit gate will open. There are also crystals, which give you a bonus, and act as a save point if your ball gets popped.
The hazards on this level are two pits and a field of spikes you have to jump over. If you hit a spike, you will lose a life and go back to the last crystal or the beginning of the level.
This level introduces a couple of elements that you don't need to solve the level. Firstly, there are spiders - like spikes that move. You can get past spiders by jumping over them or walking under them.
This level also has an inflator and a deflator floor section. The inflator puffs the ball to a larger size, and the deflator shrinks it to the smaller size. There are only 2 distinct sizes.
The ball starts in a puffed state, meaning that you can't go through the small hoop, so you need to go the other way. Understanding inflators and deflators is key to this level.
When you are big, you can bounce higher. You can also float on water; you sink if you are shrunk. The level introduces a booster, which is not needed to get through it, in fact the booster is something of an inconvenience causing you to miss some crystals in the shaft.
This level introduces a trampoline floor (slate colour), on which you can increase the height of your bounce, if you keep bouncing. This is needed to solve the level.
There are no new features introduced on this level, but the dexterity needed is considerably greater than for level 3.
This level is about moving in the vertical direction, with the aid of inflators and deflators to float and sink in water, and some boosters that enable you to float in air, or climb shafts. There's a field of underwater spikes to be crossed, but these can be avoided if you are clever about it.
This level has trampolines which need to be mastered, and a couple of horizontal spiders that can catch the unwary.
This is the first really difficult level. Good dexterity and timing is needed to get past the 4 spiders to catch the last remaining hoop. You'l probably snag the crystal in the process, meaning that your save point stays inside the spiders.
The level starts with diagonal drain pipes. Although no new features are introduced, existing techniques are combined to solve some puzzles of how to get through the level. Once you have got through this level, it's easy to remember how you solved it for next time. There isn't very much physically challenging in this level.
The most difficult level of all. This introduces diagonally moving spiders, and requires some agility to complete the level. The first half is a high speed gymnasium, with many high hoops, crystals and trampolines, and a few spikes in annoying places.
The second half looks impossible at first. What is needed is to jump on top of a hoop, rather than through it, using the hoop to get to a higher platform. Although the exit gate is visible to the right, it's inaccessible as it's guarded by spikes; you can only get to it from behind.
The penultimate level combines existing elements, but has a maze like quality. It's easy to forget a hoop and arrive at a closed exit gate.
The last level has some new features, by way of sky and clouds! It's all about being the right size, and supercharging your ball with boosters, together with finding the right surface to bounce against and material to bounce through.
There are quite a number of extra balls lurking here, but they are pretty useless as this is the end of the game. I have yet to find all the hoops - it seems as if there is always one short (somebody correct me with a /msg if I'm wrong).