Small disclaimer note: I was given a beta version of this game, but I was unable to test it or I did not make time for it because I had my own effort. I played the comp version.
Time Crystals of Cythii features you, as an elf, who dozed off and let some powerful crystals get stolen from right under your nose. You had one simple job, and now you have a bigger, tougher one: to descend from your comfy magic tower and retrieve them. Below are mists leading to five different places in time. Not just any places! Each one is a famous historical disaster waiting to happen: the Hindenburg, San Francisco before the 1906 earthquake, Krakatoa, the Titanic, and London just before the Great Fire in 1666. The game also gives you a watch, with an idea of how much time you have. It's way more than enough for all but the trickiest puzzles, if you do things one at a time. While there's some suspension of disbelief here, such as "why did the bad guys hide the crystals and not use them for evil purposes," TCoC is well put together, both the individual scenarios and the overall puzzles. Apparently this was written to augment a game that was much crueler, but even without that contrast, it's a really good effort.
TCoC is wide open at first, though you will pretty quickly sort out the smallest areas. At first I worried this gave imbalance: London in 1660 had only two locations, but San Francisco had a whole ton of them despite having the same population. Not to be a stickler, but when you have these roads you can go down in San Francisco but not London, it feels restrictive in a way the Hindenburg, which can only be so big, doesn't. But I think it works overall as a way to help you get started, as even in the largest areas, there's stuff to chip away at, at first. You get one item to trade and one to use to discover a new passage of sorts, in the small areas. It's pretty clear which is which.
The scenarios, as you'd expect from the listing, give lots of variety to TCoC without needing weird randomness, so it's never dull. I think the Krakatoa scene is best, where you get to befriend a monkey and also have to find a way to visit a ship off the shore. One of the crystals is there, and while it's never explained how it got there, going through the puzzles is really satisfying.
Which I believe well outpaces the small stuff I'm noting below. The good stuff works great, and you can only say so much without spoiling. For instance, in Krakatoa, there's pretty clearly something off the island, and finding it and making it there is a sequence of neat puzzles. While the stuff I'm not sure about, it's sort of complex to explain why, e.g. "this was for a jam with a tutorial required, and some puzzles seem a bit advanced, so once the jam is over, people will forget about that." So those not interested in technical stuff can stop here and take away the TLDR that this is definitely one of Garry Francis's better games, and it kept me occupied and was well-paced, and for whatever reason time travel games just Make Me Think more than most, so these ideas spilled out.
And I can't say any of the points dented my enjoyment. The time travel feels convenient and not forced or trivial. It felt like I was making raids and doing a bit more each time. In Krakatoa, this went beyond mapping, as there was a lot of why and how to figure out beyond the mapping in San Francisco. What's on the water, and how do you get to it? I'm the sort of person who likes to think "gee, how can we do this even better." So this is what I came up with, because I have a hard time unseeing certain questions. All this is fiddly and really only the difference between "smooth game" and "very smooth game."
First, the Titanic has a small snag with one of the solutions (apparently there are alternate ones, and the one most apparent to me was trickier.) You have to jump over a gap, and it's tough to know how much time is there. I think it was mostly the case that I was really involved, and I didn't notice the time, but I do wish there had been some sort of warning, especially since valid parser verbs that throw a parser error count as one move, or one minute. I ran into some situations where I had to figure the right verb, which was logical, but it still cost time. This feels contrary to the tutorial spirit.
Also, recognizing TCoC is in PunyInform, and features are hard to squeeze in, it would still be neat to know when scenarios are complete, or have an option for that, especially since this is a tutorial jam--maybe have a gem or something that tells you, okay, you're done here and don't need to go back. Most of the time, it's relatively obvious, but it's one of those things where if a person forgets something, and they scramble, they see possibilities that aren't there. A little surety would help. Also, having a way to know when an item is useless would help. This above and beyond "keys you find in area X open a door in area X" -- which I'm grateful for. It kept things logical. But of course having some items cross time boundaries gave challenge and made sense. For instance, NPCs from a different time period would be impressed by anything from the Titanic.
The NPCs that are there, well, it's a bit odd to walk on to Hindenburg past Nazis, especially since you are an elf, which is not very aryan, and you're probably not wearing the proper uniform, either. But the Nazis just sort of sit there and twiddle their thumbs while you hand a document to someone important. I mean, the small girl or hobo in San Francisco won't have much to say. The baker closing up shop in London is brusque too. The Titanic passengers are not going to bother with people or humanoids they find beneath them.
I also had a problem with finding how to carry stuff there is one part of the game where you need your hands completely empty to operate a vehicle, which makes sense, although it's pretty weird just to be holding a key. You know what to do, and you know probably also that you need to wear something, but part of me thought "No fair! I'm only carrying a key! That doesn't inhibit me that much! I can palm it!" So it feels like a specific excuse to reject the player would be in order.
So, yeah, my complaints here really are just that you have timed puzzles that are a bit too stringent, and there is some imbalance with the areas, and I'd have liked to see more, but there are enough good puzzles as is. You'll have a fun time not being a pedantic worry wart like me.