Honestly what I most wish for is Glulx support on Vorple. That would really move things along. Like I pointed out in the other Vorple thread, it’s incredibly easy to blow the Z8 limits even with fairly small projects in Inform 7, unless you choose to eschew some commonly used extensions.
HL will certainly play on Zoom. I recommend saving frequently.
Gargoyle’s scrollback has always been fine for me. You might want to tweak the config file to have a visible scroll bar:
scrollwidth 8 # set to 8 to make a nice scrollbar
scrollbg F0F0F0
scrollfg D0D0D0That helps, but the specific problem I have is that if I start typing before scrolling all the way back down, often it takes a very long time for Gargoyle to begin accepting input into the command line. (That is: scroll up; start typing; say “whoops”; scroll back down manually; wait fifteen seconds; letters I typed start to appear.) It may be worse with longer scrollbacks.
Admittedly this may be a problem with my computer which right now is not displaying text as fast as I can type but it seems particularly acute with Gargoyle for some reason. (Wade has also talked about weird scrollback I guess?)
Anyway this is more on topic for a Gargoyle thread; I can at least choose whether Gargoyle or Zoom works better for me.
Ah, right, that. I remember that discussion from some other thread too.
Re Vorple: there are a bunch of things I want to add to Glk, and Vorple appears about four steps down that path. I am working on a blog post that will lay this plan out.
(It’s the same plan I’ve had all along, but I’ve actually written some code for the first step now.)
None taken 
I have sketched out notes on how to rewrite the text buffer handling in Windows Glk to support a scrollbar, but I’ve not done any coding work. My enthusiasm for IF-related coding is at something of a low point, so it’s unlikely this will happen any time soon, but perhaps it will get done one day.