CSTal II purposely chooses moves that are not necessarily the best or safest. It does like to play in a manner like Mikhail Tal, attacking and complicated. Unfortunately, CSTal II does not appear to be available (though an earlier version is available at Ed Schröder's Free Chess Downloads). However, there are several other renowned programs that are.
Note: These programs work in Windows XP and earlier OSes. If you have Vista or Windows 7, I recommend that you download D-Fend Reloaded. It is a front end for a program called DOS Box that allows playing DOS games in the newer Windows OSes. D-Fend Reloaded makes the process of setup easier on the end-user.
WChess 1.05 (authored by Dave Kittinger) is available for download (with Dave's permission) at this link.
Here a a short description of WChess's play by CCC resident Fernando Villegas:
It has been a pleasure. It is not only the program and his moves, which are rarely found in other programs -when his King fianccheto appears blocked by a king pawn of his own, at once bishop goes to h 3 or 6 to give it some play- but also the feeling of going back in a nice time machine.
This has been an spectacular month, indeed. With D-Fend I have recovered almost every DOS program I ever had or wanted to have and played it... And now Wchess, the best of all them.
Socrates (Aegon 1995 version; authored by Don Dailey)
Zarkov 2.6 (authored by John Stanback)
Now (authored by Mark Lefler)
Socrates, Zarkov, Now, and many other DOS chess programs are freely available at Ed Schröder's Free Chess Downloads.
* I have been informed by Charles Browne that CSTal II was not a DOS program. Instead, it was a Windows program (which can be seen by examining the screenshot I posted). I will correct my mistake by writing an in-depth post on CSTal II in the near future.