Considering I have not played either of them, it's hard to compare and tell you why DX should be played earlier. Plus, I'm not a fan of diablo style games. So, I'd say, the best of the Diablo saga are the cinematics, and the original diablo didn't have particularly good ones? Just guessing there, but considering when it came out, I doubt it's anything amazing. Diablo, IMO, is just a loot whoring repetitive clicker with bland to no story; it doesn't hold a candle to the intriguing storyline and emerging gameplay of DX. But hey, I'm a fanboy, so what am I going to say, right?

To prevent this post from listing most big games more recent than Homeworld, I will restrict it to the only game I want to play and could have played, but never did: Portal, because it is tied to Steam.

I have played Half-life, so Half-life 2 is not such a big loss to me. However, I really wanted to play the original Portal, but not so much that I would submit to DRM. I wish it was available on GOG. :-)

If anyone knows a way to get this game and avoid the DRM (in a legal way), please let me know.

Download it and turn it offline. Problem solved.

Thanks. What about Teenagent? You think Deus Ex is better?

Half-Life Episodes
Fallout Series
Mass Effect Series
Witcher Series
Ultima Series
Divinity Series
Diablo 3
Far Cry 2 and newer
Call of Duty
Total War Series
Homeworld Series
Lucas Arts Games
All games not on GOG with DRM
Probably many many more

Look it's not going to kill you or your pc. There is nothing wrong with using it for limited usage. Portal 1+2 are worth it.

TONS of them. In the early days of DRM/Steamsclusivity, I kept a list. But since I'm a strict-no-DRM-on-my-games guy, the list is huge. Sadly the list of those I have played since the "Era of DRM" began is shorter.

But I'll include this one: Half-Life 1. I only played its TFC multiplayer component. Its own multiplayer, and single player, were awful from what I saw in others' playing.

A few key games: Civ5, Diablo 3, Deus Ex 3, Skyrim, Sims 4, Half-Life 2... Lots of dodges bullets in those shitty games, thanks DRM!

Have my upvote!
It's not everyday you see someone who plays a lot of Hatoful Boyfriend and has never played one of the COD games.
Just don't like 'em, that's all.

It's interesting how greatness is so subjective. Sometimes I can see how something is well done and would be loved by many ppl, even if I am not one of them. Other times I have favorites that get me laughed at. I might not be normal, but tests are ongoing.

I haven't played it and I don't know much about it, other than I have a gift code of it. So I'll go with my biased blanket statement that Deus Ex is the best game ever made and say that yes, it's better than Teenagent.

Although I wish it was better than Deus Ex. I've been wishing for a game better than Deus Ex for almost 15 years.

Dead Space series,Mass Effect series..There are more newer titles that i can't think of right now
From older titles i've really never played Deus Ex until few weeks ago,and any Wing Commander title whatsoever
Myst is another one.Just doesnt seem my cup of tea

Is that a good game to learn the D&D rules?

It's definitely simpler than the others, also quite a different game, but it might teach you some basics without overwhelming you - mainly some famous spells that you'll probably find in most of the other games, too, and possibly also the basic attributes and how Armor Class works, at least in the old editions used from SSI Gold Box games like Pool of Radiance to Infinity Engine games like Baldur's Gate (Neverwinter Nights is a different matter again.)

There would be lots of those, too many to talk about. I'll just mention a few that I never played but would want to eventually, like:
The Witcher 2 - for a time being I still don't have a PC powerful enough to comfortably play it, also I have only played the prologue and a bit of first chapter of the original,

Mass Effect series - actually I'm not sure if I really want to play these games, but I hear they don't take long to beat so I might give a chance to the first one at some point,

Haven't got into any of the S.T.A.L.K.E.R. sequels, though Clear Sky is still too demanding for my hardware. Dark Souls is another big one I really need to try, seems like this series has all of the qualities and challenge that I'd appreciate in a video game.

I could also mention here a few notable JRPGs I really wanted to play when I got into retro gaming, but decided not to bother after FF VI which bored me to tears after first 10 hours that I got through twice. Generally those were the kind of games I was thinking I'd like the most from 16 and 32-bit era so this disappointment pretty much made me to lose interest for the 16-bit gaming altogether, for few years anyway. Now I mostly choose action RPGs, action-adventure and shooters.