I know this is coming late, but I just peeked on the forums.
I think you can only get a gamepad to work with this game through something like [url=]http://joytokey.net/en/[/url].

You have to manually map keyboard keys to your controller.

This game came out long before console controller support became a standard feature for many games.

Hope this is helpful.

Edit: actually, pressing ESC during gameplay opened up a menu with a controller option. Very rough, but seems to work. Compatible with my logitech f130 in xinput mode.

I did the ESC menu config, but it wouldnt recognize my controller (original Xbox One, via official cable)
or maybe I'm not being able to set it to change bindings correctly, it's not intuitive in the least

I had controller support for games on computer back in 1979. My Apple IIe had games with controller support like Droll, Hard hat mack, Conan ect. Don't know why pc never had it.
https://www.youtube.com/watch?v=sNe0CwXbLh4

I still play those games on my pc with applewin emulator