Since I am still pretty much stuck in the last generation of consoles I am currently buying and trying pretty much every game that I think might have some interesting element in it, this after all isn't much of a problem when a used game only cost just 5€. Going next-gen where games cost 70€ might turn into a painful experience.
Anyway, one thing that really starts (did it ever stop?) to annoy me are the invisible walls and pre-scripted events. A recent offender is Brothers in Arms on the XBox. One can see that it doesn't try to be a run-of-the-mill WW2 FPS, since it introduces a new mechanic namely the suppression fire and flanking (previously seen in a better implementation in Full Spectrum Warrior), but yet it utterly fails at being that realistic shooter that it tries to be. Why is that? The reason is the same why pretty much every other FPS fails to provide anything that remotely reassembles a realistic experience: invisible walls.
A nice example of how stupid the invisible walls are in Brothers in Arms is a level in which one should take out a machine gun. Frontal attacking is of course a big no-no, so one has to move around it. Well, easier said then done since on the left there is no "around". The whole way is blocked by a huge stupid invisible wall, great, especially when it is not obvious that this actually should be a wall. The solution of course is to take the right path which leads one through a bunch of houses and gardens to finally take out the machine gun. So why is this bad? Easy, it destroys every tiny last bit of immersion that might have been in that game. Nothing takes one more out of the moment then not having to think how to solve a situation, but to try to figure out which way the level designer intended one to go. The whole game simply turns into a path finding experience around invisible walls instead of being a simulation of a gun fight. Brothers in Arms is of course by no means the first offender, Half Life 2 was full of that stuff and worst of all was probably Call of Duty 2, but in general you can find that stuff in tons and tons of games, you probably can find more games with them then without.
To make one thing clear, the problem here isn't the invisible wall by itself, one can't expect a level to be endless. But a level should be large enough to freely walk around in it. Don't place those invisible walls two meters from the path that I am supposed to go where I basically have to run into them when I don't exactly follow the predefined path. Also make them obvious, make them a lake, a river, a building or just a good old high stone wall so that I can see that there is a impassable wall and not a magic thingy that won't allow me to go further. There is of course another kind of invisible wall, not the one that marks the borders of a level, but one that is in the level itself, this kind is especially annoying. In Brother in Arms you have plenty of 50cm high stone walls, which look like you can jump right over them, except of course you can't. You can't shoot over them, but not jump. In a game without a jump button one could overlook such a blunter, because the underlying mechanic is obvious, even so a little stupid, but in a game with a jump button it is just ridiculous to not be able to tell which walls one can jump over and which one can't.
Well, what else can I say? One has to look no further then Operation Flashpoint to see things done right. The only wall there is, is the sea and you don't bump into it, you drown in it. And of course the land area you have is gigantic, it would literally take you hours to walk from one and to the other. This comes of course at a small price, the graphics are not so hot as in other games. But in terms of immersion it simply blows most other games away, since you really can walk to each and every point you will see in the game, you are never stopped by anything, except of course enemy fire. Operation Flashpoint of course is by far not the first game, flight simulations have had no invisible walls for a long long while and games like Midwinter didn't have them either (that was back in 1989, just to put things into perspective).
The other annoying point I mentioned: scripted events. Lets just say that in one level I died because the tank I had to protect was destroyed. No biggy, I restart at the last checkpoint and try again. What happens 30sec later? A cutscene starts and the tank gets destroyed. Right, the very tank for which destruction I failed the mission previously gets destroyed seconds later in the "mission complete" cutscene. Way to go. What idiot had that idea?
To sum it up: Games that behave stupid, destroy immersion, Brother in Arms does plenty of that, but so do most other games. Almost 20 years after Midwinter developers still haven't managed to turn their games into interactive simulations. And by simulation I don't mean that a game has to be realistic, it just has to follow consistent and logical rules. Mario64 does that to a much higher degree then Brothers in Arms. This is of course a weird comparison, but both Mario64 and Operation Flashpoint have some of those very qualities I miss in so many other games and that is the reason why those games stay fun even after years of playing while most other games already bore me when I haven't even solved half of it.
Honorable mention for in-game stupidity: "Splinter Cell: Chaos Theory". When you run out of ammo you would expect that you can pick up enemy guns, well, not here, if you are out of ammo you have to pretty much restart the level from scratch, since you can't pick up anything.