Knockout competitions are fun things, aren't they? Full of excitement and drama, and because they're so simple, you'd think they'd be easier than a league to put into a game. And in thinking that, you'd be wrong - at least as far as this game goes.
The biggest concern is in coping whenever you've got fewer entrants than you expected. A league can simply adjust the number of fixtures everyone plays in order to compensate but in a knockout, playing fewer games in one round will affect those that come later. This is worth considering, because with so many competitions and possibilities, it's next to impossible to guarantee that something won't go wrong somewhere and render a knockout short on teams. It won't necessarily be a bug or an oversight either - the Europa League has differing numbers of entrants depending on whether or not the holders are participating in this season's Champions League, whilst in the English League Cup, teams playing in Europe get byes to later in the competition.
The game needs to be able to react to this. One possible solution would be to cater for every possibility by creating several formats and choosing the one that works, but that's awfully wasteful. Instead, I decided that knockout stages should be able to take control of their own destiny.
By telling the game how many teams are supposed to reach the final, the rounds that some teams get seeded into automatically, and how many teams are expected to join midway (think the CL failures dropping into the Europa League), any knockout competition can adjust its format. All I need to do is tell the game what rounds might possibly be played - the League Cup actually has a preliminary round that has only been played once, but if nine English sides are in Europe in a given season, it'll turn up.
Seeing this work has been hugely satisfying because it was a major cause of headaches over the last while. Knowing that a competition will be react to changes takes a lot of pressure off, as the whole thing is less likely to break down because things didn't work out entirely as expected, and in football, you just can't expect anything.