Disclosure: I do most of my non-MMORPG playing on the XBox 360, so my viewpoint is thus green-coloured.
I am a big fan of the old Ghost Recon/GR Island Thunder FPS (plus Morrowind/Oblivion, naturally). You were given an objective (plant a bomb, rescue a pilot, kill everything, recon an area, etc) or two, and two teams to command, and it was entirely up to you how, when, and with what direction or path you used to accomplished that. I especially liked the two-team ability, as you could have true (realistic) flanking, containment, and covering operations.
With rare exception was there anything “triggered”, and I don’t think any of the enemy actions were scripted (besides general AI programming). You had the run of the map, entirely free-roaming, and 95% of the time you could take whatever meandering way you wanted to get to the objective. They were fun, and I’d still play them except they don’t sound right on my 360 system.
Of the newer batch, Rainbox Six: Vegas is one I find the most enjoyable - but it is very, very linear. There is an illusion that you have choices, but those choices are primarily of the sort “do I rappel down rope A or take ladder B?” There is also a fair amount of triggering (cross a threshold, have X enemies appear from the ceiling). Enjoyable and realistic in many ways, but I couldn’t do many things that in real life I’d do because the game specifically prevented me from it (best example: early mission where you approach the casino entrance and are carefully directed along the path by conveniently-placed cars/obstructions).
I could make the same assessment about the Splinter Cell games, too. You are given the impression that you have lots of freedom, but in reality you really only have a few paths (and I mean “paths” in its most restrictive sense) from which to choose, and you can’t do even basic things like you’d do in real life (like laying prone).
In part from what I read here, I picked up Call of Duty 4 last night, and I played through about four solo missions. Superb graphics and intense action, plus the promise of great online action. But…it takes linearity and defined paths to new heights. Even in the “wide open” I’ve found invisible walls that wouldn’t let me do something basic, like go behind a house.
COD4 is spectacular and state-of-the-art in many, many ways, and is assumedly the best we can get right now. Which leads me to ask: are wide-open, non-linear, minimally-scripted off-line first-person shooters dead and buried?
If there ARE any new ones (to be clear: counting only the single-player aspects) for either the XBOX or PC, please share. Gears of War & BioShock are also very linear, and Halo 3…sadly, is probably closest to being free-roaming, but I’m looking for something a bit more 20th-21st century.