Gamers in the mid-90s might remember spending hour upon terrifying hour playing Hexen: Beyond Heretic. The technology might have changed, but now you can get reacquainted with the realm of Cronos in this port from the same developer that brought us the Doom and Heretic ports. However, this game only comes with demo files – you have to provide the genuine article.
Hexen GLS is still the game you remember, but it's been cleaned up a little around the edges. It supports high-resolution screens, dynamic lighting, enhanced particle effects, and controller/Xperia Play input. The dev also plans to keep adding improved graphical effects in future releases. To play the full version, you need to place your hexen.wad file from the original game in the Hexen GLES folder. There might be a little bit of a hiccup requiring a restart after installing new data, but re-launching should take care of it.
If you want a blast from the past, Hexen GLES is going to run you about $2.14 in the Play Store. Just make sure you dig up your "game disk" first.