DOOM (DOS Player) allows you to play original DOS game on Android.
The Union Aerospace Corporation has been experimenting with teleportation technology on Mars' moons Phobos and Deimos. After early successes, something goes wrong. It seems the scientists have opened a gateway straight to Hell. Phobos base is overrun with demonic creatures, and the whole of Deimos simply vanishes. A squad of marines is sent to Phobos, but all except one are quickly slaughtered. It falls to the surviving marine to grab some guns and strike back at the demons.