The last of the games to feature Id Tech 1 is right here...
Not kidding, Strife combines RPG-style elements with FPS-style action of the Doom series. The weaponry available in this game include the crossbow, which uses two types of ammunition each with their own effect, the assault rifle, which is weak yet fast (yet sounds like a poison dart gun), and -my all-time favorite- the flamethrower, which is powerful and deadly yet consumes ammunition fast, apparently a bit faster than the assault rifle.
Enemies available include the acolytes, which act like foot soldiers wielding assault rifles, the sentinel, which is a flying drone that fires red lasers at you, the stalker, which is a spider-like drone that comes up to you and scratch you with their metal leg, and the templar, which isn't actually a drone or a robot, but a man in a hi-tech suit of armor that fires their signature weapon, the mauler (which can disintegrate you when you are hit several times with this).
Now about the action. Strife's enemies can either attack you or leave you alone (mostly templars and acolytes). Some enemies can respond to alarms, which activate once you step on a green line that acts as a scanner to let enemies know you are there and they'll attempt to kill you.
Want more? There is an inventory system that lets you keep items such as leather armor, a "targeter" device, an environmental suit which protects you from radiation, and a field surgery kit which is vital for you when confronting the final boss.
Now Strife featured RPG-style elements such the aforementioned inventory system (even though it's not like that of other RPG games), interacting with characters, and so on. Now most of the characters such as Macil and Richter are given voices as they are the most important of the game. Right, Strife is the first game to feature voice-acting, which is later used in most other games such as Half-Life or Doom 3. And you know what? Strife is also non-linear. That's right. Strife uses a modified hub system to make the game more non-linear (even though it follows a linear storyline). The hub system was taken from HeXen, as if you might've known. Yet you'll learn what the story is yourself once you first tried it out.
Get this one now. You don't wanna miss it.