Armour-reduction and the black hole generator don’t work, presumably this is the same as with any other kind of “debuff” effect. However it does this isn’t shown when scanning it.
It’s best to use direct damage effects. Things like the gauss gun might work spectacularly against regular ships but won’t do much against the guardian.

Bugs:

Sometimes you can’t get an audience with other races. Quit and restart the game, then continue.
After a successful trade agreement, I’ve had it respond in the wrong way when I ask it to break an alliance with another race. It keeps claiming success with the trade agreement.
making a planet into an orion planet doesn’t work — addressed by the 1.3 patch though.
Sometimes a colony will vanish even when there are no ships around. You choose to not bomb it, and it dies anyways.

Annoyances:

Moving in and out of screens which have individual sound takes a long time. Argh, that’s annoying.

Game annoyances:

The Alkaris turn on you without notice, even when you’re on good terms. Sigh. This is the same with several other races. Even if allied with the Darlok’s they’ll sabotage you and destabilize your relationships.
The game cheats and can send drop-ships before it takes a planet.
There are situations where you cannot win. Everyone is fighting everyone else, but there’s a call to vote just as you’re rising up. Everyone votes against you and you can’t get enough of a word in edgewise to not end up pitted against them all. Sigh.

spiralofhope

Master of Orion – (1993 game)