To help survey the zones of battles you've got access to an overhead map capable of displaying enemy positions and the ability to periodically perform thermal sweeps of the area. Along with all your other fancy tools like thermal and night-vision goggles, a snake camera to peek under doors, and a variety of grenades types, not to mention the bevy of firearms at your disposal, you prove to be quite the prepared counter-terrorist agent. The problem with the single-player is there just isn't all that much reason to use any of them, since it's ultimately such a superficial tactical experience.
Take, for example, your ability to command your squad to post up next to a door. You can use the snake cam to paint targets in the adjoining room for priority kills, instruct the squad to silently walk in and start blasting, and have them blow the door (which is now limited use) or lob in a grenade. Though each method of assault has definite side effects (blowing open the door stuns the enemies, for instance), there's not all that much need to use careful consideration in selecting methods, as your squad is quite powerful. If you give them a few seconds to engage the enemy, you just have to pop in the ever-present second entrance to the room and pick off any stragglers. Should your team get knocked down, you can just order them to revive each other with magical hypos or do it yourself. You will have to be somewhat cautious, however, as downed squadmates can eventually bleed out once knocked down, forcing you to reload from a checkpoint.
Bumping up the difficulty will of course add to the challenge, and for me made the game more entertaining as it elevates the tactical elements above arbitrary levels, except for in one particular stage. Later on in the single-player campaign there's an extensive sequence where Ubisoft completely removes the squad from your control, like was done for a bit in the first Vegas. Not only is this frustrating as you're denied the ability to effectively flank and can be killed after only a few shots, but it moves against the foundation of the franchise. That being said, it's Ubisoft's game and they're free to twist it however they feel fit. If they're trying to turn Rainbow Six into something like Halo or F.E.A.R. with a cover system, that's their prerogative. It's just disappointing to see such a development, something presumably borne of market forces and a willingness to appeal to a wider range of gamers, mostly because that particular section plays so poorly.
There's a fragmented story as well, filled with characters that randomly chirp up on your com system to give you excuses to advance to checkpoints, disarm bombs, and rescue hostages. It's not particularly well written, filled with personages barely given enough strength of character to be considered stereotypical, sloppily presented, and unworthy of your attention.