I heard that the Interceptor/UFO sequence is a minigame yet there was no tutorial. Is it a minigame? What are the controls and rules...?!
Well, I guess it qualifies as a minigame, but there's not really much to it until research + engineering opens up more options. As it stands, you close in on the enemy and automatically start attacking it. If you think your interceptor is going to get destroyed you can order it to withdraw, and that's it.
Via research, you can unlock one-time use power-ups that give you what are basically different options during the fight. They must still be constructed. These alter your ship's offense and defense in effect, and do who knows what else. I've never actually used any though I have unlocked one or two.
And as of now I have 3 power-ups, two of which Shykin mentioned in the comments: