Never heard of it, but after a quick read from various sites it seems that it's easy to play and has flexible systems to mess around with, with each game being not too different from each other mechanically but different enough to not feel like you're playing the same exact game. Forbidden lands doesn't have zone based movement but I believe the others do. Apparently certain resources require rolling dice to see how many resources to get and how much of said resource you use up or something. Another person mentioned that have to roll a lot of dice and you might fail your rolls often anyway due to how the system works but I can't say for certain.
Overall I can't really find many people with bad experiences with it so I guess you should at least try out one of them. Alien and Forbidden Lands seems to be the most positive.
I find it strange how many YouTubers dislike Twilight 2000, calling it too depressing.
Answered your own question really, most Jewtubers don't like to think about anything bad unless its against someone they don't like. They rather black and white where they're on the white side.
YouTubers also don't like that Mutant Year Zero and Forbidden Lands allow you to work with slavers.
Fucking...so
that's not
too depressing but Twilight 2000 is? Some people...probably goes back to what I just wrote and they're upset they can't enslave people they don't personally like or try to roleplay a slaver slowing seeing the light and becoming a liberator. Or ERP reasons, these people are probably degenerates.
I assume they are lefties, or virtue signaling about Ukraine
You'd know, because terminally online armchair politicians
will let you know if they're virtue signalling.
In the past I've had players confused by the concept of Mr Johnson or have no idea what a Lovecraft even is.

Christ. It's not even an age thing given how much Eldritch shit is in media these days, this is just willful ignorance. As for Mr.Johnson, that's a bit more understandable, if you're referring to my nigga from the Muppets.
He enjoys mini wargames, but doesn't know the first thing about fantasy, cyberpunk, or nerd shit in general.
More of a historical guy I take it? Does he play any vidya or watch movies that you can use to help him get into TTRPGs? I would recommend easing him into those genres in the future (I mean, how many games
aren't heavily nerd shit) with games that are enjoyable but don't go too autistic into nerd shit (which is pretty hard given who makes these games and for who).
Tunnels and Trolls maybe? It was made buy a guy who found the rules for D&D (I believe this was OD&D since TnT was released in 1975) Or perhaps-may Allah forgive me for uttering its name-D&D
5e. But without all the other shit they want to you buy, just straight base 5e with some minor changes you might want to make to ease your friend in. Hell the
Alien TTRPG you mentioned might be perfect since it has a good source material (the original movie, if he hasn't watched the movie he should be beaten) and from what I'm reading is easy to get into, has pre-made scenarios for less GM work, and has mechanics that allows the player to add on to the conflict by themselves with stress dice.
Forbidden Lands too, hell maybe even
Twilight 2000.
If he ends up not being into
any nerd shit (despite being a wargamer lol) you can try more grounded things like
Fiasco which doesn't even need a GM,
Beyond the Wall might help with it's more tame fantasy and more strategic style of gameplay (you're friend might be well suited for it since the main gameplay loop is making your village stronger and protecting it from dangers from what I'm reading). Also comes with "character playbooks" that are similar to pre-mades but still require you to fill things out. Essentially it gives you your job, purpose, story beats, whatever the fuck but lets you fill everything else out, so a good middle ground and helps makes your player more engaged with their character. It's OSR though so keep that in mind.
RuneQuest might be good too but I haven't played that, but it's made by Chaosium so it's probably good.
I would also recommend your friend to do his own research and find out which games he might like the most, of course you'll have to help guide him. Throw some suggestions and briefly explain what they are but make him actually look at what you show him so he'll get a better understanding of it.
Blackgate will definitely help, has all kinds of neat shit but...maybe it might overwhelm him. So here are my final questions:
What kind of person is he?
What war games does he like?
What Setting(s) does he usually play? More details will help.
While looking for more examples I came across this...
thing. I'll let you read it for yourself but here's some choice words:
Dream Askew gives us ruined buildings and wet tarps, nervous faces in the campfire glow, strange new psychic powers, fierce queer love, and turbulent skies above a fledgling community, asking “What do you do next?”
We queers were always living in the margins of that society, finding solidarity, love, and meaning in the strangest of places. Apocalypse didn’t come for us first, but it did come for us.
We banded together to form a queer enclave
What lies in the rubble? For this close-knit group of queers, could it be utopia?
Basically a post-apocalypse game made by people who are queer, for queers, about queers and their queerness, queerily. And of course they mostly mean lesbians (butch dykes specifically) given the images I'm painfully looking at. Did I mention they're queers and this is a queer game for queer people to be queer? Wait a second...this looks familiar.

MOTHERFU-