I can't get achievements in this game, also the Steam In-game function doesn't work. May this problem related to the fact that the game is in Flash? Anyone has the same problem?
In Windows, the FlashAchievements.exe that ships with the game is broken for many people. I've contacted Edmund with information about a fix, not sure when that's going out but he says he's working on it after this update goes out, in the meantime the fix on this page works:
You want the 1.5 version, the second link to a zip on that page. This is for windows, on the Mac there's nothing at present.
If you're paranoid like me and don't want to download things from the internet that you're not sure where they come from something that works for me is this:
I unlock some stuff and finish my run (steam has not registered any achievements). Shut the game off. Go into Isaac folder in the steam tree and remove FlashAchievements.exe. Go into Steam, verify integrity of files, Steam notices FlashAchievements.exe is missing and downloads it. Start the game up and get the achievements.
The annoying this is that this has to be done each time the game is started up, i.e. this works the time the game is started right after verifying and getting FlashAchievements.
That said; well done on fixing the issue InsidiousForce.
When I was trying to get the Krampus achievement, I noticed this as well. The achievement popped fine in Steam, but the overlay wasn't really working properly. I wanted to take some screenshots for my answer, but I wasn't able to do that either.
Some people were able to fix this by upgrading to the latest flash client, however.