Yes, true, probably the only change would be String to AnsiString. But in fact, I think I only used string in some constants, and correctly used PAnsiChar in the others
I'll change those constants though.

To become a Steamworks developer, right now it is a bit difficult. You have to pay 100$ to be able to put your game in Greenlight, that is basically a voting area for Steam players. The games with more votes are selected to go into Steam, and then you get an oficial invitation from Valve to become a partner.

However there are rumors that soon (possibly next year) this will change and possibly the process will be easier allowing more people to get in.
I think they will remove the voting system and replace it with something else.