Hi! I figured I would jump in here and talk about the forum threads that you have linked too!
This thread has to do with Brutal Legend and the known bug list. You should have seen the original list! We fixed a ton of stuff in that game to make sure that everyone could play the game. The remaining bugs in that list are much less severe and do not affect a very large group of users. So in that thread, yes we did say that we are no longer actively working on the game. But we definitely did not abandon it and we have continued to ensure that it works with the new OS versions.
This one has a report of the game not working under windows 8. This made me pretty nervous so we put together a windows 8 machine last night and I spent a good part of today testing the game on it. I was able to get pretty far without any issues. I know that we did test Brutal on windows 8 before it launched, but I wanted to be sure before responding here. When we tested it we also went through and made sure our other games worked on it as well. Good news, they all work! We have also been testing on windows 10, which works as well. We get some issues into our support email box as well concerning issues on different OS versions, but they are almost always fixed with drivers or steam file validation. But again we are definitely not abandoning our games! Though I should have responded to that forum thread, its pretty hard to ensure that we hit all of our forums, we try and get to everything but sometimes things slip through.
Hack n' Slash was not abandoned but we did finish work on the game and released it as a 1.0. We even added steam workshop support so that people could add mods to it is as well. We continue to provide support for the game and intend to make sure that the game is working for users. Like I said earlier, some threads have fallen through some cracks, its hard to hit all of them, but we are here to help and provide support.
Also you mentioned Iron Brigade and how it is only available for windows, I don't know exactly how detailed I can be about that. But it is no minor task to bring that game onto Mac/Linux. But we do still support that game and recently removed Games for Windows Live and even after releasing with steamworks networking support we spend a good deal of time tracking down network stability issues in the game to ensure that players were able to enjoy it.
So all that being said, we want people to enjoy the games that we create and ensuring that our games work on new OS versions is important to us as well. Before every big OS release we make sure that we test our games and that they are functioning properly. And if there are major issues we always find ways to address them.