I personally love "Deathwalker;" it's one of my favorite season one episodes.
It's great to see what a Dilgar looks like, and this is the only time we ever do. And Jha'dur definitely portrays the horrors that the Dilgar are associated with. Knowing this lends greatly to the "history" of the Earth-Dilgar War, which helps one to understand somewhat the hubris of many in EarthForce when it came to Earth's wanting to investigate or whatever the Minbari prior to the start of the Earth-Minbari War.
First, we get Jha'dur saying that since she's created an immortality serum that it'll be great for her in that though the Dilgar are currently viewed by pretty much everyone as horrible people, but that everyone will turn to praising them for her discovery. That's bad enough, full of arrogance and vengefullness. But then we get a second hit and see first-hand how horrible Jha'dur really is in the massive pleasure she derrives from the thought that since the serum requires the death of a living person in order to create it for use by someone, people will fall to preying upon one another for it.
Of course the possibly biggest fun for me in the entire episode is the quick sudden twist at the end when a Vorlon ship suddenly pops through the jumpgate as Jha'dur is on a shuttle bound for Earth and blows the shuttle, Jha'dur, and the serum to smitherines. Kosh's statement, "You're not ready for immortality," is a great moment for his character early on. It keeps him mysterious, of course, but also hints at how advanced the Vorlons are. The ambassadors of the League of NonAligned Worlds are pleased that the horrorible Deathwalker is now dead, and there's little beyond filing a note of complaint that Earth could do in response to the Vorlon's actions because of how powerful the Vorlons are. Very nice.
I like that we get to see Ambassador Kalika again. I said it when they first popped up in "The War Prayer" and I'll say it again here, I like the look of the Abbai and wish they had been in the show more.
We also get to see three League ships in this episode: the Drazi, the Vree, and the Ipsha. I'm glad that the Drazi ships were eventually redesigned making them a bit more normal than the one in this episode. The Vree ships too were redesigned, but I kinda wish we'd see the old designs too and have had the Vree add both types of ships to the fleet Sheridan assembled. As for the Ipsha, I wish we'd actually seen what an Ipsha itself looked like and not just the ship (I'm unaware of any background aliens in the show being the Ipsha, if anyone else is, please point them out for me). I really like the design of the Ipsha ship, but it honestly looks like it should be a really advanced alien species's ship and not just a member of the League. I'd almost go so far as to say the Ipsha ship would have looked really cool if it had been the ship of one of the races of First Ones with that floating, glowing globe in the center.
Na'Toth had some great moments in this episode, it was a treat as always when the lovely Ms Brown brought Na'Toth to the screen. I liked how when G'Kar comes to pick Na'Toth up from Sinclair, though she's in trouble and upset at Sinclair for not allowing her to fullfill her shon'kar, Na'Toth stops on her way out and salutes/bows/whatever to Sinclair. It was almost as if she was saying "up yours" under the guise of being respectful.
And then we have the B-plot of Kosh hiring Abbut to record pieces of Talia's psyche "for the future." It definitely keeps Kosh's weird factor high and shows us yet another weird character in Abbut.
"Crab Nebula!"
It would kinda be nice to have a novel or something to endingly tie together Talia's character and that crystal beyond the tiny bit by Garibaldi saying that it might be useful with the Control personality overtaking Talia in "Divided Loyalties."
"Deathwalker" is definitely an episode I enjoy a lot from season one.