Confession time - I didn't really want to replay Dark Forces II. I had a decent enough time on my first playthrough, but the repeat didn't have much to offer me. I first tried to find all the secret rooms, but that lasted approximately a level and a half. The game did not let me alt-tab out while it was running, so going back and forth between the game and a guide did not work very well. I had to shut it down every time I wanted some information from the walkthrough. It just wasn't worth it.
That just left the dark side powers as my main draw to return. Unfortunately, they sucked. I don't know what I was expecting. I guess telekinetic blows that tossed enemies around like rag-dolls. A force-choke that lifted a victim into the air, where he would flail helplessly as the life drained from him. Lightning that would cut through groups of enemies like a scythe. It may be that games like Mass Effect and The Force Unleashed have spoiled me, but Dark Forces II's powers felt dull and weak to me. There was never a point where I felt like I was better off using the Force over a gun.
There was an alternate ending to the game when you played as a dark-sider, but it made absolutely no sense. Kyle Katarn kills his friend and co-conspirator, Jan and taunts Jarec by saying that he will seize the power of the Valley of the Jedi for himself, and in the end, he does, becoming a new galactic emperor. I don't even want to go into all the ways this violates the logic of the setting and undermines the established traits of the characters involved. Suffice it to say, it follows the "evil means you have no motives besides being a dick" pattern that I always found to be absolutely ridiculous.
My final assessment of the game is that it is not as historically important as its predecessor, but it holds up better when taken purely as its own experience. The levels are still a little confusing for my tastes, but they don't have quite so much early 3D jankiness and the ability to look up and down with the mouse is an improvement which by itself makes the game about a hundred times more playable.
I think I will remember this game fondly, even given my rather disappointing second playthrough. It's still more primitive than I need to put up with, given the options available to me, but there was no point where I was aggravated enough to curse the game, and thus no great flaws that I might seek to blame on its primitiveness.
I still have three games to go in the series, but I feel like I'm over the hump. They may not keep getting better, but I doubt they'll get worse. As long as the other games can be at least as competently executed as Dark Forces II, I'll be fine.