Since somewhere in 2013, Valve made some backward-incompatible changes to the way Source Mods work.

Thanks to Hardtimes and d10sfan on steamcommunity.com, there is now a hotfix/patch to make the mod playable again.

Head over to the download page to get it!

Discontinued support

Sorry for the inconvenience but support for Portal: Prelude is no longer provided.

We are aware that there is some problems running the game with the free version of Portal on Windows but there's nothing we can do. Valve replied to someone by saying: No Source mods are included with the free Promotional Offer [...] These mods are only included with Valve games purchased through Steam or from a retail store. You must purchase a Source game included in this list. There might be a solution here and there, but it's a bit tricky. If you're looking for help, head over the forums which are still working and up to date!



This mod was released in 2008 and we all moved in favor of other projects or totally stopped working around modding. This website itself is no longer maintained since Google dropped most of the features of Blogger in May 2010 and we can't update it anymore without a major overhaul (which is not going to happen).

Mac users, read this!

Portal: Prelude was never supposed to work on Mac.

Valve ported their Source Engine under Mac OS without telling anyone and especially not me (which seems fair anyway). Now I don't have the time, motivation and knowledge to port the game to Mac myself, but I can provide you with a zipped version and instructions on how to make it work. The free Mac version of Portal suffers from the same problems than the free Windows version (see above). It's a bit tricky but so far it worked when we tested it on a Macbook.

Old website follows

Friday, October 9, 2009

Happy Birthday Portal: Prelude! Posted by Nicolas (permalink) Today, it's been exactly one year since we first released Portal: Prelude. It was a hell of a year, but even if there's still some people discovering or playing the mod for the first time right now as I write, things highly cooled down. We tried to calculate the total download count, but this is just too hard to do after one year. Some websites have gone down, some websites don't count downloads, some others resetted their counters and some didn't even changed for a few months. There was an approximate additionnal 200,000 downloads during the last 25 weeks, which means people still download the mod on an average basis of 1150 times a day. That's still a good score. According to statistics and extrapolations, the mod was approximately downloaded 1,000,000 times since the release. But that still doesn't count magazines, sharing websites and peer to peer softwares, which probably represent at least 50% more players. I guess you, people, liked what we did. So, thanks, and if you don't get what I'm talking about, refer yourself to the 'Reminder' article.

Wednesday, July 1, 2009

Reminder Posted by Nicolas (permalink) For the few of you that are still arriving on this website for the first time, welcome! Take your time to understand what's going on via the links on the right and feel free to download the mod if you wish. Dont forget that there's a FAQ answering most if not all of the most common questions I received by e-mail during the last months. Remember, to play the game, you need Portal, this is not a standalone game, and the mod won't appear in your Steam games list if: You don't own Portal at all.

You never launched Portal from Steam.

You're using a pirated version of Portal.

You didn't install the mod properly (unlikely since it's automated) Anyway, thanks for passing by and feel free to talk about the mod in the forums if you wish. But please, be polite, be efficient. It's been almost 9 months since the mod was first released and I'm now working on something else. Sorry if it takes me a while to do some support or reply to your messages.

Sunday, June 28, 2009

Cheaters aboard! Posted by Nicolas (permalink) A week ago, I praised our new player, Stimich, who managed to break almost all the time trial records on Portal: Prelude. Today, it has come to my hears that there could be a problem. Some fellow speedrunners warned me about some suspicious details on Stimich's videos and I decided to give it a little investigation. After a few hours of research on the Internet with my friend Google and with the help of one of the former Prelude record holder, I indeed found quite a few suspicious details. First, this guy is commenting out on a video named "How To Cheat In Portal Without Cheating" where he actually states that he's trying to cheat. Then you can find all of his Portal time trials on some weird website named "Cheat Grabber". And finally, when you take the time to download and decode his time trial videos, there's a problem. Here's a random part of his video where he's just moving his aim from the ceiling to the ground in order to shoot a portal.



As you can see, in a normal situation, it takes something like 8 to 10 frames to move like this. But at the beginning of his video of the 12th room, there's a little problem.



On this section, he's moving the same way almost 4 times during half the time needed. He's even changing his aim from front to behind in one frame. I slowed it down to 1 fps and one of the shots he turned and shot in 1 fps and then the next frame he was aiming directly back where he was before. This is just impossible to achieve, even with superhuman powers. This cheat can be categorized as a Tool Assisted Speedrun and it's such a shame that people are trying to cheat us for no reason on a free mod. That's not like if there was some prize for the winner. On this Youtube page, you can find a demonstration of a Tool Assisted Speedrun, and as you can see it's perfectly invisible for the game, but not for the eye. As a conclusion, all of Stimich's scores are going to be deleted from the ladder and replaced with the previous ones. Stimich is also banned from any future ladder entry, unless he proves his innocence.

Monday, June 22, 2009

A challenger appears! Posted by Nicolas (permalink) For those of you who aren't really fond of scores and speed runs and don't regularly follow our challenges ladder either, be advised that there was some huge changes recently. During the last months, the scores were somewhat freezed and nothing changed significantly. But a newcomer appeared two week ago and now, he's slowly crushing every score, beating 10 time trials out of 14. As you can see, Stimich seems to know how to think with portals more than anyone else. This run is particularly impressive. If you think you can stand up to him, feel free to try, but I think we reached some physical limits around these scores. I don't think someone will be able to do much better, apart if we're talking about some bots playing Portal: Prelude, of course.

Sunday, April 5, 2009