When Harmonix, the creators of Guitar Hero, decided to leave the Activision fold, skate-metal developer dudes Neversoft stepped in and bashed out Guitar Hero III.
It was great, it sold plenty, and nobody other than hardcore fans and games-biz watchers would have known it wasn't made by the original team.
The only problem was that Harmonix had raised the bar by creating the considerably more attractive Rock Band for EA, which took the basic Guitar Hero format and turned it into an all-singing, all-drumming, hideously expensive four-player frenzy.
Rock Band still isn't out in this country (on Wii, at least - CVG), but the general consensus among those lucky enough to have played it is that it's amazing, it's revolutionary, it's the best thing ever to happen to music games, and, well... Guitar who?
So, despite Rock Band not really affecting sales of Guitar Hero III, Neversoft have gone back to the drawing board for the sequel. And it's not unfair to say that they may have been resting that drawing board on a couple of copies of Rock Band.
Guitar Hero IV is no longer just two players and a couple of axes. Now there's a drum kit, a bass and a microphone for the singer. Sounds familiar. Looks familiar. Is familiar.
The drum kit is a more advanced affair than the EA product, boasting velocity-sensitive pads for its three drums, two cymbals and a kick pedal.
The guitar, which is still in development, is said to have more buttons further up the neck, for a more realistic feel (Rock Band also has this) but you'll be able to use older Guitar Hero controllers as well.
The microphone is a standard USB model, which means you'll be able to use ones from other games.
The main difference between this and its rival band simulator is the level of customisation. There's a hefty character creation mode and the option to build your own on-screen instruments from a list of parts - you can even choose gold-plated pickups and different types of strings.
It's not all cosmetic, as the guitars and drums can be tweaked to put out different sounds during the songs - and you can actually compose your own music for it as well.
Neversoft hired a fan who'd modded the PC version of Guitar Hero to enable customised tracks, and he's helped create a comprehensive editing suite called Music Studio.
Here, you can tune the guitar buttons to a particular scale and jam along with backing tracks from any of the huge list of built-in songs.
Once you're up to speed with playing the plastic guitar like the real thing, you can hop into a sequencing program and design an entire track from scratch.
Guitar parts, drum loops and a bass track - you can't add vocals, although there's nothing to stop people singing along.
Once you've got it sounding the way you want, you can play it like any other song in the game.
So, if your favourite music isn't on the roster - which now includes pop, hip-hop and electronica, as well as the usual rock - then with a bit of talent and patience you can probably recreate a close approximation yourself.
Online? Or not?
For those of us a bit short on talent and patience, other users' songs will be available to download - on some consoles, anyway.
Despite the tracks taking up a minimal amount of space, as all the sound data is on the disc, there's no confirmation that Nintendo will allow the potentially copyright-infringing service on Wii.
However, they're said to be very keen on the idea and are looking into ways of implementing it on Wii.
Here's hoping they sort it out, because downloading songs created by a community of users is a huge benefit that makes GHIV really stand out from any other music game.
No word on pricing either, but we do know it's coming out later this year, in plenty of time for Christmas.