So “Batwoman”’s Crisis crossover is rather instructional, at least in understanding what’s going to go wrong with it (the crossover). The writing. “Batwoman”’s script is all right. Not great, but leaps and bounds over the previous one. Even if the performances get a little shaky and they’re trying too hard to foreshadow, but Don Whitehead and Holly Henderson’s script does something “Supergirl” couldn’t manage. They make a decent “hour” of superhero adventure TV.

Albeit an hour with absolutely nothing to do with the regular “Batwoman” stuff, including having Ruby Rose play second-fiddle to pretty much everyone and then have this weird “straight-coding” moment with Melissa Benoist, which is a pointless Bechdel fail. How is it possible the Arrowverse shows can’t find a writer capable of not screwing up at least one of the characterizations. It’s not like comics got to have writers’ rooms or paid assistants so you’d think there’d be someone checking on this stuff, but whatever. It’s a short scene and soon gives way to the simultaneously successful and not successful Kevin Conroy cameo.

How does “Batwoman” get away with never having Batman on the show? Go to the future on an alternate Earth during the Crisis and introduce old man Batman Kevin Conroy (who voiced the “Animated Series” cartoon for years along with a bunch of other cartoon features and video games). Shame Conroy’s really bad at acting. Though director Laura Belsey gets major props for trying to hide it. Most of Rose and Conroy’s scenes together consist of Rose standing and listening to Conroy speak, close-up on Rose, maybe an over the shoulder from Conroy every once and a while because that way Conroy’s speaking but not having to emote. It’d be more impressive if the Conroy cameo added up to anything, but not really.

Meanwhile, there’s the Jon Cryer’s Lex Luthor hopping universes to kill Superman over and over again, leading to a shockingly good Tom Welling cameo. I’ve never seen “Smallville” but Welling seemed like he’d impress as an actor but he’s good here. Is able to play off Cryer without much setup. Good stuff.

Then there’s Brandon Routh getting to put on the Kingdom Come Superman outfit and do a Superman Returns sequel, with plenty of references… then a sad Joker one. And it turns out… Routh really was a lot better at playing Clark Kent than Superman. Maybe he’d have grown into the part if Returns had gotten its Man of Steel but… also maybe not. Though he’s in old age makeup and CG-buffed or something to play old man Superman here so who knows.

Oh, right, then there’s Grant Gustin and Caity Lotz (the best performance in “Supergirl,” decidedly not feeling it here; she seems exhausted) going on a secret mission with Green Arrow fille (Katherine McNamara, who’s not good) and exhausted too but still lovable Matt Ryan. Dominic Purcell shows up for some comic relief, along with an actual nice surprise cameo.

Candice Patton’s also around, participating in the continuing Tyler Hoechlin and Elizabeth Tulloch “Superman Family” backdoor pilot. It’s still cute enough, more so here just because the episode’s a lot better television than the “Supergirl.”

Shame the Arrowverse producers didn’t care about consistent writing… with this crew on the whole crossover, Crisis might have had a chance. But hopefully it won’t ever be as bad as “Supergirl”’s entry again.

Got to be fair and point out there’s less LaMonica Garrett in this episode than the “Supergirl,” which means less absurdly godawful acting and just regular tepid TV performances and not even many of those… it’s a very professionally executed episode.