This is an overview of the IF games that worked best or meant most to me in 2019, plus a couple of bonus games that weren’t released this year but that it took me this long to play. There’s a range here — some of these are short, some are long, some choice-based, some not, some commercial and some otherwise.
I didn’t have nearly time to play everything that I might have wished to: it was a very busy year with a few especially wild months. So I didn’t play very many of the IF Comp games, or any of the EctoComp pieces, or many recent releases from Choice of Games.

I played two striking pieces by Porpentine Charity Heartscape this year.
One is available to the general public: The Soft Rumor of Spreading Weeds, a companion piece to With Those We Love Alive, published by Sub-Q. This one explores what it means to be the Empress in this universe; what sort of life she has; what her cruelty tastes like.
The other was a multi-player piece, created specifically to be the keynote of an event: organized by Karlien van den Beukel, and presented to the public at the Victoria & Albert Museum in February. I was in the unique position of presenting the work — a role for which Porpentine had written specific instructions and extra text — and I talked a bit on Twitter about what it was like and how it worked. It would be impossible to capture the experience entirely in another medium or context, but this was one of the more interesting IF experiences in my life, and certainly one of the most interesting multiplayer works.

Storyscape is an app for free-to-play IF on mobile. There are a lot of these out in the world: Choices and Episode have been around for a long time, and have been followed by lots of other apps of varying degrees of quality and imagination, including Fictions, Story, Chapters (Choose Your Romance), Moments, and My High School Summer Party, among others.
In this landscape, substantially the best piece I tried was Titanic in the Storyscape app. I have not yet played all the way to the end of the storyline, but the premise and the first several episodes are by Meghna Jayanth, and they are top-quality work. Expect very non-standard characters; a setting that feels well-researched but never pedantic or onerous; and many many fun choices. Highly recommended.

The Ballroom by Liza Daly tells its story through text that morphs as you change elements of the scenario — becoming by turns a Regency romance, a high school dance scenario, a spy thriller or a police story. It’s an elegant use of textual variation that draws on the legacy of works like Space under the Window. One of the most formally inventive pieces I played this year.

Pray to Your God(s) is a short Twine piece by Vian Nguyen. It describes an act of prayer in the author’s tradition and culture, with autobiographical details that bind it to Vian’s lived experience; but it also provides opportunities for the player to decide how they would engage with this type of ritual themselves, and asks what they might say to the departed.

Dull Grey, by Provodnik Games. Dull Grey presents the story of a young man who is deciding between two possible careers, in a state dominated by Soviet-style centralized planning.
The story presents vignettes, and then, from time to time, offers a choice — the same choice each time — about which career he would like to pursue. It is essentially an entire game that consists of one big Track Switching Choice structure. There is also a little more possibility than the game initially makes obvious.

Sisi Jiang’s Lionkiller is set in China during the First Opium War. It tells the story of a woman who disguises herself as a man and becomes a soldier, riffing on the legend of Mulan. The characters are nuanced, the setting rich in detail. There is also a lesbian romance arc, at least in some versions of play.
One of the stronger pieces of IF writing I’ve encountered this year, and very much recommended.

Turandot, Victor Gijsbers. This is a ChoiceScript game but very different from anything that would appear under a Choice of Games branding: largely linear with minimal branches and no visible use of stats, it draws its inspiration loosely from Puccini’s opera of the same name, but entirely revises the plot, so that the titular princess requires Prince Calaf to traverse a death-trap-filled dungeon in the spirit of classic games (a bit as spoofed in Inhumane).
Turandot drops in quite a few references to classic IF and sometimes wanders into gratuitous in-joke territory, but the actual concerns of the piece — about agency and consent, about our responsibility for the situations into which we place other people, about the value of truth and the possibility of atonement from a position of monstrosity — are anything but frivolous, and can be read even by players not familiar with the source materials.
That said, I need to put a warning on this. There are also times when the game’s characters make mean-spirited sexist, racist, and homophobic jokes; and some descriptions of torture and incidents of dubiously consensual sex. Personally I found that the philosophical and moral argument in play made a good case for why I should encounter these objectionable elements. I know other people for whom that wasn’t the case. And I can also understand why one might not want to be exposed to those elements regardless of their reason for existing.
So handle with care.
Bonus game:

I finally got around to playing SPY INTRIGUE (furkle) properly this year. It was an amazing experience and I recommend you check it out if you haven’t gotten to it yet. My review will give you some idea of what to expect from it.
Did anyone else write about the event in February? It seemed groovy from your description.
With “some choice-based, some not”, for the “not” are you just meaning Liza’s?
I don’t know of any other write-ups of the February event, I’m afraid.
Non-choice-based: yes, just Liza’s in the end. This is probably not a meaningful statement on the state of the field, given how busy I’ve been and how limited my time was, but I didn’t click powerfully with many parser games this year, and didn’t have as much energy as usual for pure-puzzle stuff, which seems to have been somewhat dominant. I didn’t even get a chance to play the IF Comp winner Zozzled ( https://ifdb.tads.org/viewgame?id=436g2gu94kxin4x7 ), though! I’m obviously missing some things that other people really liked.