ADOM II License

Additionally you are required to abide by the following licensing terms:

You will not decompile or reverse engineer ADOM II.
You will not use ADOM II as a whole or parts of ADOM II in other projects.
You will not modify ADOM II or any parts of it.
You will not redistribute ADOM II in any way. The download via http://www.adom.de is the sole source of distribution.
You will not charge anyone for using ADOM II.
You will not challenge the intellectual property rights of the author.
You accept that ADOM II comes without any warranty of any kind and that the author cannot be held responsible for any damage to your system or data accidentally (by bug or system error) caused to your system or data.

>>6
Closing the source wouldn't stop users from complaining, in fact their complaints would be against a "black box" that doesn't "work" and since debugging/reverse engineering closed source programs by end-users is rare this would be forwarded to the author.
With open source, the user has the option of modifying the program behavior to suit his needs such as "adding feature X/Fixing bug Y" if they have the skills or hire some other programmer.