To jump straight into gameplay: skip to 01:31 directly.
So, back again with another DOOM video. This time it's neither Brutal Doom nor Project Brutality. Just regular classic vanilla DOOM but with an assist companion mod which features Caleb from Blood. If you've seen my recent gameplays about Brutal Doom & Project Brutality then you have noticed me using this assist which offered great help in Extermination Day especially. So I decided how about I try this one out with classic vanilla DOOM and try on beating the Nightmare difficulty? Even with the assist, things were still difficult but not impossible, since in most case I have a hand that can help me secure the sector together. To make things more easier, I also included a generic marine assist alongside Caleb who will patrol around looking for enemies but unlike the undead gunfighter, he won't accompany us in the upcoming battles ahead nor he will respond to the call which only Caleb does. As a result, this generic marine is on his own, whether he lives or dies none's business.
The only mods that are used are the assists and a special mod which alters the vanilla monsters a little bit (only included the SEEFRIENDLYMONSTERS flag on all of them so that alongside Doomguy, they also keep in mind Caleb or any allies that are on the slayer's side. Caleb in this version uses the following weapons:
1) SMG
2) Rocket Launcher
3) Grenade Launcher
4) Plasma Gun
5) BFG 9000 (rarely)
That's about it :)