I'm keen on finishing my write-up of this group of flashpoints in this series, so let's get on with it. The grand finale of the mid-level Revan storyline!
The Foundry is an Imperial-only flashpoint that has been in game since launch and was originally designed for levels 35-42. It's the last part of a story arc that spans four levelling flashpoints in total, with the first two taking place on Republic side and the Imperial part of the story starting with Boarding Party. Since 4.0 they are all tacticals accessible from level 15 onwards and also have a solo mode in order to enable people to just see the story.
The story that you've been told in the quest Call to Arms up to this point is that the Emperor supposedly allowed a powerful Jedi Master to escape from captivity so he would lead the Empire to an even more powerful, hidden installation called the Foundry. In the previous flashpoint you stole a Republic ship to approach said installation more stealthily, while this instance is about the main event of invading it.
The Foundry is basically a giant droid factory, so it's no surprise that most of the enemies you fight in it are droids too (and there are a lot of them). Interspersed are a couple of Jedi, plus in that bit where you exit the main installation for a while there are those moon slug things, one of which is the bonus boss.
Aside from said bonus boss, there are two fairly unremarkable droid bosses, plus that one Jedi where I'm never even sure whether he's supposed to be a boss or not, but he does drop some crystals as far as I recall.
What makes this flashpoint interesting however are two fights: HK-47 and... the Jedi Master.
HK-47 is a fairly interesting fight in terms of mechanics, though to this day I'm not entirely sure how much of it is intended and how much of it is simply due to bugs. Apart from add summons, the key mechanic is that HK will disappear into a giant machine core every so often to power up, which you have to interrupt by clicking on four panels on its outside. However I've also seen HK stand in the core's spot with no actual core visible, while simply being immune to all damage, and people getting one-shotted when they tried to attack him. I guess we're willing to forgive that because he's HK - being a bit of an unpredictable killer is in character.
And of course at the end we have... Revan! Sadly he's not nearly as cool in terms of mechanics as he could have been. The fight is quite impressive visually, with Revan drawing from a mix of Jedi and Sith abilities while going on about how he uses the power of the Force in balance. In practice however, there's simply a lot of dodging out of circles and not much else. His body mysteriously disappears at the end, leaving the door open for a possible return of the character, which Bioware eventually made a reality in 3.0.
So... I guess I kind of already spoiled it in the paragraph above, but it just so happens that the mysterious Jedi Master in charge of the Foundry turns out to be Revan. He contacts you on the holo shortly after you kill the first boss, offering to not treat you badly as his prisoners if you give yourself up peacefully. Of course that's not an option.
Later you run into a holographic projection of HK-47 who explains that his master has devised a plan to eradicate something like 98% of the Imperial population because they all have some traces of Sith blood in them and the galaxy needs to be cleansed of that. In other words, Revan has turned into a genocidal maniac and needs to be stopped. So you kill first his droid and then the man himself.
The flashpoint ends with the Empire taking control of the Foundry, a super powerful installation that is sure to win it the war, just to never be heard of again.
Overall the Foundry is another fun romp, if maybe filled with a bit much trash. (It's one of the few places where I'm not too bothered if the rest of the group wants to skip the two bonus quests.) Getting to fight HK-47 and Revan is kinda cool.
Here's the rub though (and I already talked about this to some extent in my Maelstrom Prison review): Putting a storyline about Revan, which is incidentally also a direct continuation of the Revan novel, into a bunch of mid-level flashpoints was simply not a good idea, because it meant that it had to be completely disconnected from the game's main storyline, which in turn resulted in it being both kind of nonsensical and not really doing the character of Revan justice. And I'm saying that as someone without previous attachments to KOTOR!
If you come to the Foundry as an Imperial player first, you kind of go: "Wait, Revan is alive? And he's insane? Why?" If you actually played through the part of the story on Republic side first, you know the answer to the first question, but instead you go: "No way the Republic would have sanctioned genocide like this, what is going on? And we're killing Revan, yet nobody ever mentions this anywhere on Republic side?" Everybody kind of loses.
After having played through all the flashpoints in this story multiple times, I do kind of appreciate the effort that was clearly expended to tie all of it together... but it's simply not good enough. Even if you play both factions, it feels like there is too much missing, mainly any sort of explanation of why Revan has turned into a genocidal maniac. Sure, you could argue that the long imprisonment by the Emperor drove him insane, but having to look for an explanation for something this crucial to the plot after the fact is not very satisfying. Plus there is the whole issue of the Foundry being this incredibly powerful installation, clearly a defining point in winning the war... and then it is never mentioned again. If you want to keep flashpoints separate from the main storyline, you can't just leave all-powerful MacGuffins lying around at the end of one.
I still recommend visiting the place to see the storyline, even more so now since it's kind of required background reading for the Shadow of Revan storyline that was added in 3.0. However, overall it definitely isn't one of Bioware's more shining examples of storytelling. Even though I enjoy aspects of it, I still find the Foundry to be the most disappointing of the lot, simply because up until then there was still room (in theory anyway) to explain some things. However, the Foundry just goes "nope, this is it", which is a bit of a letdown.