What do I have to look forward to?
Fun combat and impressive "immersive" stuff peppered with dumb shit that wastes your time, like endless trips through asteroid fields. Be careful not to let your teammate get any kills at all, because if they do, the game thinks you're terrible and puts you on the losing route. You're the most important person in the universe, your influence over the war is outsized to the point of total absurdity, and the entire course of the war is determined purely by how many kills you get. You can pass all missions perfectly and still end up in deep shit if you didn't personally get most of the kills.
The first game is pretty fun. The second is more of the same but with a comically poor story that will make you laugh. After 2, they start with the live action FMVs, which quickly got to be too much for me. I know everyone finds great ironic fun in how cringingly bad it all is, especailly when real professional actors like Malcom MacDowell are forced to read out embarrassing and nonsensical lines. But the story is just so deeply shit that it's borderline offensive, it's like watching the worst Star Wars fan film you've ever seen, except one that actually stars Mark Hamill (and is thus worse than the worst Star Wars fan film). Hamill's performance is so bad that it's unreal, and your character goes from being an annoying jock in the second game to... well, Mark Hamill, in the third. I don't know if he thought he was coming across as cool and edgy, but he actually comes across like he doesn't want to be there and is angry at being asked to take part in the entire project, hissing and spitting every line out. On the rare occasion that the game actually let me play rather than forced me to watch a bad movie, I sometimes turned my ship right around and rammed into the flagship, just to send myself/Hamill up in a big fiery ball of flame.
The terrible story in WC2 is tolerable because it's ultimately so dire that it's impossible not to marvel at it as a piece of inadvertent comedy genius (the Japanese character dying in a literal kamikaze attack, which is played completely straight as tragic drama, is absolutely gutbusting, and the dazzlingly abrupt "romance" arc suggests that the writer has never interacted with any other humans in real life). But WC3 and 4 pretty much force you to watch reams and reams of this piss-poor stuff before finally letting you play the actual game, and the joke's on you, because it turns out that the game is not even as lukewarmly fun as the first two, for the brief moments where you're actually allowed to play it. You're basically forced to watch a full, terrible movie, which Chris Roberts probably made into a game because he secretly knew it was too shit to even pass as a straight-to-TV B-movie that not even people stoned out of their minds and half-conscious while flicking through channels at 2 AM would willingly watch, and your only reward is to play a really middling space combat sim that's already been surpassed by other games at that point.
The first is a really great piece of videogame history though, it does some incredibly cool stuff for something from 1990, things that you don't see in games today.