Oh yeah, I remember that "shields" mechanic was pretty annoying. You'd point your ships at the enemy, they'd shoot and nothing would happen, other than that stupid green glow. That's because they weren't smart enough to close to a range where their weapons *would* be effective. It got replaced with the armor mechanic, which is a lot less controversial (although less spectacular in its results).
There was also a time when you didn't get a little "startup base" with all the energy structures and the force field when you started the game, you just had a command station. So, the first twenty minutes of every game would be exactly uniform across all games.
Raid starships used to be much more effective. To the point where my default action each game would be to tech up to MK III and build them all out, then go nuts blowing up guard posts. They still weren't that effective against large groups, but guard posts fell like wheat before the scythe. Can't do that as much any more, which makes me kind of sad. You can still use them, but only for shooting relatively undefended guard posts. And you can pretty much skip the MK I model, since it's not immune to missile any more.
Heh, there was a time when Arcen decided to start re-tooling some of the art, but dropped the project after changing a few art assets. Among other things, the space docks and command stations used to look different. So now you have this weird disconnect where some of the stationary facilities look like they're made out of concrete while the other ships still use graphics from Tyrian. Not that it matters much since you're probably going to be spending most of your time zoomed all the way out and looking at the ship icons instead.
Also, a final story, at some point, the games got to be so large that people's high end gaming rigs started choking on the large numbers of AI ships hanging out in the back of the galaxy. This is how carriers and barracks were introduced, to mitigate that.
