Here is the demo of Heretic 2
The demo is the original x86 linux version by Loki, patched to handle 800x480 "widescreen" pandora screen. It use box86 and gl4es and is really playable, at least on a gigahertz model.
Note that keymap is not changed and should probably be modified to be more...
Here is Eric's Ultimate Solitaire Demo, a demo of a commercial card game.
The game is the original Linux x86 version from Loki. It use box86 to run. The game use old gtk-1.2 lib (emulated x86 version here), and is a bit tall if you are using X11, but is perfectly playable.
Here is the demo of Descent 3 for Linux
This demo is the original Linux x86 Loki version. It use box86 and gl4es to run.
You will need to configure the keymap to enjoy it.