The iPhone 4S has a main processor twice as fast as that of the iPhone 4, and a graphics card seven times as fast. This not only means that existing games and apps will run significantly faster and more smoothly, it could also herald the way for more big advancements in mobile gaming. Last year’s Infinity Blade game (for iPhone, iPad, and iPod Touch) is still regarded as probably the most impressive game on any smartphone-sized platform, even compared to the offerings available from dedicated handheld gaming consoles like the 3DS and PSP2.

Infinity Blade II, which will make good use of the iPhone 4S’s increased processing and graphics power, will get a release a couple of months after the 4S, on12 December. It’s already looking very, very good, building on the tactical hand-to-hand combat depth of its predecessor, but with better graphics than ever. It also takes advantage of the new iCloud service available through the iOS5 operating system, allowing you to keep saved games in the cloud, available for use from any iOS5 device. So, you can start playing Infinity Blade II on your iPad, but then carry on the same game later in the day on your iPhone. If, as is likely, the sequel keeps the same quickfire format, that should work perfectly, allowing you to get a few minutes of play in while waiting for the train or even queuing in the supermarket.

Game developers have welcomed the new iPhone, though most of the smaller studios will continue to produce games that are backwards-compatible with older iPhone models and earlier versions of iOS. Many new games will be designed with high-end graphics modes that do take advantage of the iPhone 4S’s improvements, even if they can still be used on an iPhone 4 or 3GS.

Apple also announced improvements to Game Center, their equivalent to Xbox Live and similar services. Game Center is intended to be more social than earlier, with friend recommendations, avatar uploads, and achievements to show off.

At present, no games have been announced that make specific use of Siri, the speech-recognition virtual assistant launched with the iPhone 4S. There are potentially some interesting opportunities there, particularly considering the possibility of using the voice like a third hand, to shout extra commands (“RELOAD!”) in hectic games, or allowing for a squad-based combat game in which you can give your AI team instructions while still moving and shooting your own avatar.

By all accounts, Siri really, reliably works, so incorporating realistic speech directly into gameplay could also work, and could be revolutionary. Imagine being able to talk to non-player characters in an adventure game, and have the game engine understand what you want. It’s more work than most game studios would be willing to put in to developing a game, but the one that does will get the headlines, and the sales.

Perhaps the most exciting iPhone 4S feature for gamers relates to the improvements in AirPlay, Apple’s application that allows for streaming uploads from your phone to your HDTV. Previously, AirPlay was mostly used to show off photos or videos in high definition, or play your iTunes library directly over your home entertainment sound system, but the new gaming possibilities are quite thrilling.

An upgrade to the popular Real Racing 2 game will allow up to four iPhone 4S or iPad 2 users to race head-to-head, with the HDTV screen operating in split-screen mode, and the individual smartphones and tablets being used as controllers and map screens. The upgrade launches for free next week to existing Real Racing 2 owners, or you can buy the game for your iPhone 4S for £1.99. The upgraded version also brings a significant improvement to the graphics, with better shading and reflections, and a much higher polygon count.

The iPhone transformed smartphone games for ever, and the latest iPhone 4S looks set to do this all over again.