Well, I hope you really liked SWAT 3, because then you’ll really like SWAT 4. SWAT 4 is just like SWAT 3, only one more. It’s basically the same game.
That’s a good thing, though. Irrational didn’t mess with success. The best close tactical game ever remains the best. The graphics are much improved, of course, and there are some welcome additions, like the ability to see through your elements’ eyes (including snipers). Also the command interface has been improved, with the inclusion of “smart commands.” (All this means is that the game has a good idea which command you may want to use at any given time based upon which team you have selected, what you’re pointing at, etc., and automatically defaults to that. Of course, you remain free to override it.)
Beyond that, there’s not much to tell. I’ve only played the first mission, but it played exactly like the missions in the previous game. You have to move carefully, and avoid shooting and killing as much as possible. You’re scored based upon how appropriate your actions were in each confrontation, and if you actually care about getting a high score (which translates into being the best goshdarned boy scout in LA), then the game becomes much, much more of a challenge. To give you an idea, on Easy difficulty, I scored a mere 60 out of 100 my first time out, in which none of my officers took a single bullet and no civilians were harmed. In fact, the suspects never got off a shot. But I still only got 3 stars out of 5 because I was a little too hard on the bad guys. I felt so bad (sniff).
Anyway, if you loved SWAT 3 and want more of that kind of action in a package that’s sweeter in every way, SWAT 4 is a must buy. If you’re feeling ambivalent because you didn’t really like SWAT 3 all that much, then I’d say you’ll probably be happier spending your money on something you’re really crazy about.
EDIT: I forgot to mention, there’s also multiplayer (one type: SWAT vs. Suspects) and an integrated mission maker. I haven’t tried either one.
EDIT Part 2: I also forgot to mention the hellishly long loading time at startup. It must preload a lot of stuff, because it takes a good three minutes–no exaggeration–to even get to the first (of like 5) splash screen on my machine (P4 1.7GHz, 1 Gb DDR RAM). After that, the missions themselves take about 30 seconds to load. Once loaded, though, the game plays very smoothly (my vidcards’s a Radeon 9800 w/128Mb).