Exits are to your right and left, and flamethrowers are under your seat. Be careful, though, as they are sometimes filled with water. If this is the case, try to club someone with the non-working shotguns in the weapon closet. Also, be careful while wandering the ventilation shafts. If you see a large, six-legged creature that looks really pissed, give him your lunch and he'll hopefully go away. In the event of an emergency, you can and will be used as a flotation device. The Plasma rifles in the forward locker are released only under authorization of an Admin, [V] God, and/or hyperintelligent shade of the color blue. Current topside temperature is 400K.
As for your questions, I do suggest diving into FSPort and its expansions, so everything makes more sense in FS2. The games aren't *too* dissimilar from eachother.
I suggest: FSPort => ST:R => (Optional) Operation Templar => Freespace 2
One word of warning: 400 Kelvin is about 260°F, so please dress accordingly.
But yes, FSPort => ST:R => (Optional) Operation Templar => Freespace 2 is the general consensus amongst us HLP members.
I second mjn.maxael's reccomendation to play Silent Threat: Reborn, rather than the original Silent Threat. Reborn has better and more missions and the story makes more sense than the original.
I reccommend playing Freespace Blue (which is a modified version of FS2 from the Blue Planet mod) instead of the MediaVPs version of FS2 because I'm told it's better balanced overall and because there's a certain mission where you get a better bomber to fly against a particularly memorable opponent than in the original version. The only downside to Freespace Blue is that there's a bug/feature where your player score does
not let you get awarded new ranks so you stay an ensign the entire campaign. But if that doesn't bother you, the advantages far outweighs the disadvantages.
As for what to play after FS2, like mjn.maxael said, there's lots to choose from. A couple of my personal favorites (though I haven't finished them yet) are Derelict and Exile. Real Life (TM) has kept me away from the last few missions of Derelict, but it's a
very good campaign that has stood well against the test of time. As for Exile, I'm currently editing the dialogue; while it's a great campaign, the dialogue and text need polishing and the project leader was nice enough to let me volunteer to edit it (although the work has been slow on my part). If you want to play its current version, feel free, but just be aware that a new version of Exile should (Flying Spaghetti Monster willing) be ready in several months. And there are a number of fan conversion campaigns that are totally outside the Freespace universe as well for your perusal. The sky is (no longer) the limit here.
