I like to write things on computers. Some of it is magic. The rest are just words.
Try checking the log.txt file in the game directory, your friend may need to update his video drivers.
By all means!
Barony requires OpenGL 3.0+ functionality to run.
The game is unable to start because it can't load the OpenGL extensions that it needs for the game to operate. Usually this is solved by updating your drivers, but if you've done that and are still having issues, it's likely your computer is just too old to play the game.
If you're on windows, check the stderr.txt file that the game produces. If you see that the game exited with a fatal error 3, then it means you'll have to update your drivers.
We've encountered the stuck in the lobby bug ourselves at times and have made measures since the last version to fix that. I haven't personally encountered it since... but I don't know if it's been completely eradicated yet. One thing that almost ensures that won't happen is to play the game on LAN, because internet play is kinda buggy and unreliable right now in general.
The "clients not being able to cast spells" bug is brand new to the latest version. We fixed it shortly after releasing and will roll it into the next version... but we kinda sorta already announced no more free updates on our devblog, so I don't know if we'll reverse that for this issue. But we're generous souls at heart, so, maybe... :)
We can provide tech support at the game's official forum, make sure to post the stderr.txt file that the game produced when you make your post =)
A new trailer for barony is in the works.
You can play the game online if you have your friends' IP address.
Ah, I see. You shouldn't feel ashamed of your English though, it is really very good. In fact if I didn't know you were German I would have already assumed it was your first language. :)
This game reminds me of Super Mario World 2: Yoshi's Island. Have you ever played that game? I suggest you do, you could pick up some really good ideas there.
EDIT: By the way, I am still looking forward to defeating your challenge:
"I highly doubt that anybody who wants to finish the game will be able to complete it as it becomes so difficult."