Have you ever played the flash version of Portal: Portal: The Flash Version? Well if you liked that I suggest you try out this: Portal: The Flash Version MapPack for Portal. It's basically the flash version remade for use in Portal. It's a really good addon and took me about 3 hours to complete. If you install it let me know your thoughts too. One more thing, the boss battle at the end is amazing, worth the download alone just for that bit of the game . Official Website
I downloaded it then realised I had miss read your description of it. I thought it was a standalone game I didn’t realise you needed the PC version of Portal to use it. I’m off to check out the Flash version now, the screenshots of it looks nice.
I played that map pack before, it gets really difficult. At the point where you get to those electrified floors it got too hard for me. I should give it another try. I didn't know there was a boss though. And it isn't Glados?
I just finished the map pack. It was longer and more difficult that the game itself. And I agree with you the end boss was really cool! Spoiler My first reaction when I saw it was what's Metal Gear doing here? Also I liked how they put that ship they mentioned in HL2:EP2 in there. I also saw some things I didn't see in Portal and I wonder if it was part of the game but they decided to not put it in or if the maker of the map pack modeled all that. For example those tubes which hold the test subjects near the end, or the electrified floors. I also heard Glados say some things I can't remember her saying in the game, like at the end she said something like this is the second time you escape.