I totally forogt to mention this but Jank Jack (X) has been released on Steam some time ago. About a month already? Maybe only a half.
Truly one of the "better"sandbox survival games. this is of course opinion based.
The game was initially an iOS game and was now ported/redone for computer systems (PC, Mac, Linux). It is basically the same game as the mobile version however with soem new gimicks.
The map is overall a big improvement. You can now zoom out reeeeaaaaally wide compared to the iOS version (given, that it is a smaller screen) and move the map around in order to orientate yourself. Big help if you want to backtrack or just to find the how far you are away fromt he surface.
The movement isn't block based anymore but fluid, you can also jump two blocks high instead of one (making it easier to reach hight places).
I think the drop rates of rarer items are higher, even on lower difficulties. The battle system was a little redone, for the better or worse. Some say it is wors (me) some say it is better (not me). However, some weapons got their big time on PC. The spear has a really cool animation and battle style compared to the mobile version and the desktop version is the only version where I like to use bows. I found bows in Junk Jack X underwhelming. The way you target is irritating and far from intuitve, most of the time you will miss because you cannot target cirectly. To explain it better: Bows in Junk Jack X behave more like artillery instead of real bows. You aim upwards and the further you aim, the further your arrow flies. That the actual screen size is too small to get a good use of ranged weapons does not really help this. And worse, some enemies NEED you to use bows because they explode after dying. Awkward.
The general downer about the combat system is however the speed mechanic. Junk Jack X had nothing like that. How fast you tapped where how fast you attacked. Tap faster, attack faster. Easy.
Junk Jack S (I decided that's how I call it now despite being not the official name) has some kind of cooldown system. When you attack your weapon swings and the whole way the animation swings you cannot attack again. Once the animation is finished you can strike. The btter your weapon tier (higher metal), the faster the animation. Sounds good on paper but Junk jack has waaaay too many different metals for that to work and with wood being the lowest tier it has to be slower than a snail.
The graphics has been a little improved. I say a little because most stuff looks the same. Enemies have been redesigned for some reason, your character has been not, nor have any of the blocks as far as I can see. Maybe this ill change in the future but I don't think so.
So far I couldn't see if you can find the purchasable premium hats of the iOS version. You can however not buy them, that's for sure and I hope this will stay this way. The premium hats were really cool and I purchased some but with 15$ for a port I think I payed more than enough to cover the costs. After all the game costs a lot less ( I think 3-5$).
There are some new enemies in the game or some enemies may appear on other planets. Bats appear now already on Terra (only underground) and there are now variations to bats. There are new sliem variations as well and some variations behave differently. I saw yellow slimes who jump very high and fast aggresively around.
Besides that I couldn't see big differences like I said, the game is the same in its core and people have to decide if they want to buy it for 15$ again (or the first time).
Finally soem summary about the game for people who DON'T know it. There is actually nothing special to say about Junk Jack. It has nothing that it differantes it from other sandbox games. It uses the regular formular. You start with nothing in a world, have to scavange wood, food and other stuff, build a shelter, dig underground for new metals and imrpove your equipment. Every night there will spawn enemies at the surface that will hunt you down unless you are somewhere inside. However, what makes the gam good after all is the massive quantity of stuff you can do, find and craft and it does very well in those regions.
There are 11 different planets you can discover with own biomes, enemies, loot and other stuff. You can cook over 100 different meals in the game (for collecting purpose). There are many treasures to find, rare items that can be only found, not crafted. You can show them on shelves and showcases. There are vast varity of furniture options to choose from and many more can be found in biomes. You can brew your own potions with different ingridients and what you use defines the effect and the strentgh of the potion, finally the bottle type defines how long the potion lasts. You can fish in water and place fishes in fish tanks. You can tame wild animals and either use them as pet (they will follow you aroudn but won't do anythign beside that) or place them in an animal shelter where you can feed them and breed new animals. They will also produce resources (depending on the animal). There are rare pets you can find or "craft".
you can find jewels and craft rings or put them into your armors and tools for stat bonuses. There is also some kind of circuit system I never got access to be3cause it is on one of the last planets.
You can collect flowers and combine two different seeds to create new type of seeds (color and flower appearance mixed randomly).
A lot of people who see this first claim it is "another" Terraria clone (why does everyone think that every 2D sandbox game that comes out wants to copy Terraira? It is not the peak of its type nor is it the only one). The game is however more close to a 2D Minecraft with copying a lot of the features from that but extpanding them further. It has actually NOTHING in commong with Terraria except it is 2D. There are no bosses or events in the game no NPCs and no real character progress. All stat enhancements come from your equipment.
Junk Jack is more of a clollector type of game. It is not a game that tries do seduce you with unique features. You have seen what it offers already in many other games, maybe better. However, Junk Jack itches my collector instinct. Whenever I play the game I don't play it because I want to reach a certain point. it is not like Terraria where you want to find a special item that you need for the next boss or like Starbound where you have to do the next quest. You play because you want to find a rare collector item. A treasure that you cannot craft yourself. This starts already with the portal chests that you need to dicover for the other planets. You search the entire planet just for a tiny chest (which is easier on the desktop plattform because of the better map). You search for biomes because they yield biome related furniture and equipment. You kill XX amount of a specific enmy just because you want the hat he drops.
Junk Jack is full of those moments and people who like exact that type of gameplay will like it. People who want a real adventure game or even a good sandbox builder will probably look somewhere else.
Also achievments. Because collecting.