Turning on each mode changes the way you interact with the world in an aural sense. Stealth mode heightens your reception of sound, so you'll be able to hear enemies much more distinctly as they walk about, while shoving the speed mode on is likely to make the music more adrenaline-fuelled, causing your pins to work overtime in propelling you through a ruined New York City. Check those screens - his feet are a literal blur of activity.
Questions on whether the amount of time you could spend in the stealth mode will be increased went unanswered - one of the grievances people had with the Nanosuit's powers in the first game. Remember that your role as super soldier isn't just all about the suit. You can modify your weaponry as well, gluing flashlights and laser sights on to your guns with abandon. This time out, there's going to be a few more things to play about with in terms of abilities, like directional bullet trails, x-ray vision and bullet deflection.
All of this is taking place in what Crytek are calling a "huge open world in which the level of interaction is limited". That does sound a little worrying, but maybe that just means it'll be a more focused experience, preferring to restrict how far you can explore back alleys and buildings in favour of a clear narrative structure.
Surprisingly, Left 4 Dead is one of the names thrown out by Crytek as to what has inspired them recently, namely the way the storyline goes on in the background and is taken on board at the user's discretion. Yet this influence only goes so far - Crysis 2 is definitely going down the direct narrative path, but the new tactical suit mode might fill in some gaps for the inquisitive, giving you details about things scattered about the game's world. Examine a dead body in this mode, for example, and the corpse's biography will fill the HUD - clues as to his demise and his backstory, yours for the reading. We're looking at audio logs version two, here.
Quickly back to the tech before we leave each other. Crytek say CryEngine 3 will be able to handle "hundreds of lights" without any performance hit, as a 'deferred lighting system' lies at the core of the technology behind them. We're not experts when it comes to this sort of thing, but it sounds an impressive claim when it comes to luminosity.
In fact, all of Crytek's claims about Crysis 2 are deeply impressive, from the new urban direction to the pruned and less wasteful engine tech. It'll take time to see whether the experience on PC has been distorted by the cross-platform interests, but maybe it will be for the best in the long run.
As long as they don't mess about with what makes FPS games so natural on the PC, and what made Crysis and Warhead so exciting to play, we'll perhaps take a little bit of compromise this time. Not too much, though.