Hey, kartezjusz2009!
First of all, thank you for your great feedback.
We've just released a new version of the game (0.2) with some features.
So, we reworked UI a little bit. I think now it should be fine with number length overflow.
"Second thing is that when you add countries, they are randomly chosen and it is possible to add a country twice."
Yeah, I know about that, but this bug is kinda fun - you can play with AI or hot-seat stile for the same country. We're currently reworking countries (so you can pick countries sharing same provinces, for example EU and Poland) and this bug should be fixed in the future.
Anyway, thank you for your ideas!