Some scattered thoughts:
A lot of work went into the UI and translation mechanics. It looks amazing. Awesome stuff.
The educational value of this game is off the charts. It does take a lot of mental work, between the puzzles and deciphering what's going on, but the result is worth it. My advice would be to resort to the clues early on when stuck.
During the second adventure, I ran into some memory errors that necessitated restarting the game, but the dev pushed an update right afterwards that should hopefully stop this from happening. I think it's tied to complexity of input and length of game history, so the best way to avoid it - if you're paranoid that it might still happen - would probably be to save frequently and resort to the walkthrough when stuck.
It wasn't immediately obvious to me that Bound Transcription in the settings is an option that can be changed to display everything in cuneiform. I knew that cuneiform display was an option because the main menu said so, but didn't realize that was the toggle for it. I wished I'd discovered it earlier, because it's fascinating to me to play through chunks of the game in cuneiform. My knowledge of it isn't good enough to play the entire game in cuneiform, however, and I found it made the 'double-click to insert' behavior more unintuitive since it was harder for me to decipher word boundaries. A lack of experience on my part.
Make no mistake, this is a very enjoyable game, especially if you're fond of linguistics and learning about different languages and writing systems. If I had to offer a main criticism, it would be that I wished the game focused more on grammatical features and aspects of cuneiform (e.g. what determines the cuneiform to Roman letter mapping? Are there certain aspects of cuneiform that get certain letters?) instead of puzzles, but this is bias on my part since I'm not hugely interested in puzzles.
Also, the second adventure made me hungry.
The comments below consist mainly of additional nitpicking.
Semi-playable on mobile, which I initialy tried. The interface, typing, clicking and all that seemed to work fine - the default layout is large and packed with a bunch of things, but I made it work by zooming out and using landscape mode. But the one thing that didn't work was hovering over the grammatical cases of the different definitions to see what nominative, dative, and so on actually meant. I gave up on mobile pretty fast since I didn't feel like wracking my brain to remember the grammatical cases, and didn't feel like I'd get the complete experience without them.
Can't copy-paste any in-game text. Annoys the part of me that wants to just put everything into Google Translate, but I just checked and Hittite isn't even available in Google Translate, so it's probably for the best.
If there are multiple translation footnotes (parser errors), the older ones fade so only the newest is available, which is mildly annoying but I can't think of a better solution. Maybe if you could hover over the older parser errors to see them in full.
First adventure took me about an hour. Fun, but I dislike that you can only (Spoiler - click to show)use the water in the pithos one time before it disappears (why?). The first time I accidentally used it to extinguish the torch instead of extinguishing the fire. Then I had to go to the riverbank and fill it again. Some experiences I had during the first adventure were akin to 'guess the intended command' (no 'guess the verb', as all available verbs are listed) since commands like 'put water on fire' didn't work and I had to use 'put pithos (with water in it) on fire' instead? Also, the aforementioned confusion between 'extinguish fire' and 'extinguish flaming torch'.
Second adventure had more unintuitive puzzles in my opinion that made me resort to invisiclues. The part I got stuck on was (Spoiler - click to show)making the reeds last long enough. I forgot about the oil and became fixated on the idea of relighting the door bar with a flaming reed, since lighting the door bar worked in the first adventure. Then I couldn't understand why that didn't work.
Third one I admittedly gave up on since it had been 3 hours at that point and I was tired. I actually identified the perpetrator on the first try, but didn't realize (Spoiler - click to show)I was supposed to dance towards him. I think I misinterpreted the tablets and thought that the king would kill anyone who danced or bowed, no matter who they were doing it to.