I sort of partially see your point here. But, it's kind of a bad take. Who are we, who are mostly getting the game for free, though of course some of us support devs we like on Patreon, to say that a dev can't release a game unless each update is lengthy. UFO has only been out little over a year, and there have been a handful of updates already. THat seems reasonable for a lone developer. There are quite a few very, very, popular and well regarded games here that only release every 8-12 months (or longer), and have much less content per update than UFO has in its one year of development time.
I do think that if you are accepting payment for your game on Patreon or elsewhere, you should make every effort to release an update every 2 or 3 months, whatever the length of the update. I know many devs don't do this, but that is my opinion. However, if the update takes a year, and can be played in less than 5 minutes (looking at you Unleashed and WVM), than I think it is fair to say something, since the dev has failed to live up to any reasonable expectations in a huge way.
But in this case, while nobody here would complain if updates were longer, I think it is reasonable. There are many, many, devs with much slower development (Radiant, cough, cough), that deserve criticism, but not 17 Monkeys with UFO.
I think he is doing a good job so far, with a very unique and fun game premise, and we should all encourage him to continue so we can enjoy seeing where the story goes.