Innumerate

I'm informed that the Polish number system is the same as in English.

Kit of agreement

I'm not sure what a "kit of agreement" is, sounds like a useful thing to own though.

Hammer time

Ok, so the hammer is not even there (as the German translation suggests), but I do like the translator's choice of words ;-).

Mutation

What on earth happened to this poor chicken?

Possessed

Why not display your grammatical error in a prominent window on the busy Rynek for everyone to admire?

Also,  this is best advice on using the apostrophe appropriately.