Fortunately, the answer to that is not much at all. Timeline wise, the plot falls slap bang between both N64 games. Grunty the witch, who was defeated by Banjo and Kazooie in the first game, is still trapped under the rock where she was left, with Klungo her minion still trying to free her. He has the bright idea of building a robot suit for Grunty's spirit to inhabit, and upon transfer, Grunty flies off to kidnap Kazooie and travel into the past to prevent bear and bird from ever meeting up in the first place. Mumbo zaps Banjo back to the same time period and it is from there that the adventure begins.

If you wanted a proper Banjo Kazooie game condensed down into portable form, then this is going to be pure catnip. Just about everything from the first game has been carried over, and a couple of the features from the second game have been added in for good measure. Bozzeye the mole carries out learning moves this time around, and Master Jiggywiggy is still in charge of opening the new worlds within Spiral Mountain. On top of this, Mumbo (his earlier, better looking self) performs the odd transformation and Honey B adds to your health bar if you supply her with honeycombs. Almost all of the original moves are intact and available, and are easy to access and use on the Gameboy's four buttons.

The game is all about the acquisition of jiggies and notes. Notes help "pay" for learning moves from Bozzeye throughout each level, and jiggies are what open up new levels. Jiggies can be earned in a number of ways, from collecting all 5 jinjos on a level, to various minigames, completing timed puzzles or pure platforming skills. In the beginning by himself, Banjo can't do very much, but once Kazooie has been rescued, then the rest of the game (along with the dry sarcastic humour) begins. Once all the levels have been sufficiently completed, then Grunty's under construction tower is opened up and the final confrontation can once again begin.

Graphically the game is a tour de force for the GBA. Every character is rendered very much in the DKC style, and in at least four directions, meaning there is a lot of graphical data being processed. This can lead to a slightly blocky look, but with the bright, sensible colouring and animation employed, this is not so noticeable. The important factor within the game is how the levels are constructed, with the transition from 3D engine into a 2D plane. Anyone who has played Zelda:Link to the Past will recognise how Rare have built each environment, with a pseudo 3D look and multiple height perspective. For the most part it works very well and is very cleverly thought out, though at times it can be hard judging how far a jump is. To this end, the intelligent shadow work comes into play and these can be watched to ensure an accurate leap.

Whilst the game looks a bit different to previous releases, it sure as well sounds almost identical. All of the main sound effects and burbling noises used to represent speech have been ported over and sound exactly as before. It may have been three years since the last game, but the sound of Grunty and Mumbo still brings a smile to the face. The level scores are brand new however, but still perfectly fit in with the general Banjo Kazooie theme. The code may well be running on inferior hardware, but the important issue is that it still truly feels like a proper Banjo Kazooie game to the senses.

Which can also be applied to the scripting. The humour is still very much spot-on, with Banjo being as dumb as usual and Kazooie sparring constantly with Bozzeye. The game is picked up immensely due to the banter and it is guaranteed to constantly make you laugh, or at least raise a smile. It sums the overall experience of the game, it makes you want to play it because it is so enjoyable to do so. There is a combination of easy and hair pulling challenges within, and the final battle, true to Rare form, will test peoples' skills. If, as a player, you want a title that will constantly keep you entertained, not dropping or getting boring, then this is one to buy. There is no over frustration, no teeth nashing or unfairness, performing well in the game is down to the individual skill of the person involved.

Sadly, the experience is over all too quickly. With only five levels on top of the Spiral Mountain hub, many players may reach the final battle within 6 hours of gameplay. Whilst there are occasional bonuses for a 100% completion, there is not much replay value apart from access to all the bonus mini games. Like Wario World before it, Banjo Kazooie on the GBA burns ever so brightly during the entire game because it has the class and quality about it in design, gameplay and aesthetics. It is just a pity that it burns ever so shortly as a result.