Make sure to install the game somewhere with just ASCII characters, like "C:\Games\is2" instead of "C:\Users\José\is2", otherwise you will get an 'unable to open file' error.
Sorry, I spent ages trying to confirm my age as 18+ on the IC-2pop-up! The 'YES' did nothing no matter what I did. As apposed to the 18+ 'YES' on IC-1'spop-up, that worked 1st time. GGGRRRR!
Then I continued down the page to.... OH LOOK SOME SUPER PERSON HAS POSTED THEE VERY THINGS I SPENT AGESFAFFING WITH!!!!!'BBBEEPPPP!'But 'BBBEEEEPPPP!' in a nice way... Honest. lol.