IQ: how it works and the numbers

Short answer

IQ is one number for your village: your skill in the six mini-games, each fading when you stop playing it. It makes your zombies stronger by up to 15%.

What it does

Your IQ is the sum of your skill level in each of the 6 mini-games, each multiplied by how fresh that game is. With skill topping out at 30 per game, the highest IQ is 180.

A game stays fully fresh while you keep playing it. Once it has gone unplayed past your grace days (a Brain Vat adds a day per level), its freshness falls 1% for every extra day, with no floor. One run that isn't a Fail restores it at once. Skill levels themselves never drop from being away.

Your IQ raises the health and damage of your own zombies by up to 15%, when you attack and when you defend. It does not change towers, the keep or the gates.

Villages run by the game instead of a player count as 18 IQ per strength band, and never fade.

How fast a game fades

Days since the game was last played	Freshness of that game
0	100%
7	93%
14	86%
30	70%
60	40%
100	0%

What IQ is worth in a fight

Skill level in every game	IQ	Bonus to zombie health and damage
1	6	+0.5%
10	60	+5%
20	120	+10%
30	180	+15%

Tips

Any mini-game run restores that game: order, practice, Daily Challenge, skip-ahead test or Trial, as long as it isn't a Fail.
Spread your play: one run in each game keeps all six fresh, which beats grinding a single game.
If you can't log in for a while, a Brain Vat is the answer.

Questions

What is IQ in Voxhorde?

IQ is the total of your skill in the 6 mini-games, each scaled by how recently you played it, up to 180. It adds up to 15% to your zombies' health and damage.

How do I stop my IQ from dropping?

Play each mini-game now and then: any run that isn't a Fail restores that game. Games fade 1% a day once they have been idle past your grace days, and a Brain Vat adds one grace day per level.