If Portal was released on it's own then I don't think it would have gotten the praise it got. However because it was a great deal packaged in with Four or so other games then you see it as a bonus mini game thats quite good! My problem with Portal however is that, the game felt like a tutorial for the last level and it was really the last level where everything started to come together and just as you were getting started, it ended. The thing is it ended with the death of GlaDOS and me thinking.... where can Portal go from here? Really I just think it was a tutorial game for people to get used to the Portal gun, a new concept before they put it into the next Half-Life game. It makes sense that they would try and merge them two games together seeing as they made Portal blend in with the Half-Life universe, that the place was being funded by Black Mesa
The gameplay itself is very easy and simple which makes it feel more like a tutorial and the only time it throws any challenge at you is on the last level. It does offer a new gameplay element I for one have never see in a game before, thats the portal gun and a first person puzzle game is quite rare too. Theres really only one thing you do throughout the whole game which is only about 2 hours long and thats shoot portals to get through the puzzle and to the next stage so it's very Doom 3 like where at the end of each level you stand in a chamber and it loads up the next one.
There is one major highlight to the game however and that is GlaDOS and much like System Shock 2 (Shodan) she makes the game what it is and really if she wasn't there then It woulda just come off as a generic game. The scripts for GlaDOS and the way she delivers the lines is just so funny with it's dry dark humour. Not everyone will understand it and find it funny, specially the younger peeps but the older crowd will love it. Theres also just lots of hidden jokes like the whole "the cake is a lie" thing that I'm sure you've seen going round the itnernet for awhile. Valve have seent he success of things like that and put it in Left 4 Dead with all the writing on the walls and hidden easter eggs like a TF2 ceral Box that gives a clue out that there might be a 10th class coming.
Theres one other thing that made Portal for me and that was the ending where it wraps things up nicely, you discover where you are and theres a joke with the cake. Also theres this great song that plays on the credits which everyone seems to enjoy and while it's not the greatest song ever made, it fits in well with the game and has some funny lines to it. You can also play it in Guitar Hero or Rockband (I forgot which one) and in audiosurf too which is great fun.
So Portal is a charmer of a game and with The Orange Box is great for the money but it isn't the gameplay that makes the game for me, it feels like a tutorial for a future title. However what saves it from being a generic disaster is the humour of the game and how it doesn't out stay it's welcome because I'd feel like if it was any longer than 2 or so hours then I would have become bored.
Everyone should play this game and if you really liked it then download Portal Prelude, it's a very well made mod that has the same humour to it made by a mod group, it feels like it could have been made by Valve. It really steps up the difficulty however, so you've been warned that IT IS HELLA HARD!
http://www.portalprelude.com/
+ Does Mirror's Edge remind anyone else of Portal?
Edit: I have to add that I just played through this game again and it's just so charming that I can look through all it's short comings and take the game on it's own merits. I loved the touches like the dark humour and the song at the end credits just pushed it to a 4/5 for me. I just feel like it falls short of a 5/5 because of the faults I pointed out. What made it sooo special to me is when I completed it I felt happy and sad at the same time that it ended so soon but it's a nice experience to have that a game can be so charming it brightens up your day.