The application requires GTK 3.14 or later and GTK VTE Widget 0.42, so it only runs on Ubuntu 15.04 (and derivatives: Ubuntu GNOME, Xubuntu, etc.) and newer. The application does not work in Linux Mint 17.x, Ubuntu 14.04, elementary OS Freya, etc.
...and requires dconf
and requires python-nautilus
There are plenty (dozens) of alternative terminal emulators. If you let me know which features are important to you, I can suggest some alternative apps.
Do you value the "splittable panes" feature? I've seldom found that to be useful & instead prefer a "tabbed" layout.
I really don't see a single standout feature that terminix offers compared to available alternative apps.
If you're looking to have "transparency", I can tell you in advance that getting that working will be a roll of the dice.
vte package maintainers have removed transparency support in latest debian version (v2.91) of vte packages,
so you need to use a repository that supplies the older 2.90 version (and your chosen terminal emulator must be compatible with libvte v2.90)
(or you'll need to track down the patched-to-restore-transparency v2.91 library built by linux Deepin project)...
...and, on an antix system, fluxbox (and probably icewm and jwm as well) doesn't natively support compositing
(so you would need to install and run xcompmgr(?) or compton to achieve transparency).