ok first of all thanks a lot! much appreciated
second, these are definitely some good ideas, will probably add them. uhh as for the buy/sell items, i'll think about it
So for the tech tree thingy, when you make a factory, you can use the money which is displayed near the oxygen, health, etc. On the tech tree. Near the change recipe, you will find something called tech tree button, when clicked, it will display that skill tree looking thing that's found in untitled space program career mode. With money, you can unlock new tiers of stuff and upgrade in the tech tree to unlock VAB like structures.
For the cloud save achievements thing, with my stupidily low knowledge on scratch, I atleast know that you can use Cloud Variable as a form of saving and for doing multiplayer. But multiplayer is not what I am implying. I am implying that you can save world's without needing to export the code, but you can export it as backup if needed but it will be saved in-game. And achievements (in my opinion) should be added (completely up to you). But incase you do add, it's like you get it on the top of your screen for building a VAB or something or reaching a new planet. And when you get the achievement and you quit, it will be saved in that one game save's achievements tab. So like when you are playing, you can click K to open achievements tab and it looks something like Minecrafts. Or atleast you can add the achievement save with the save code that's exported everytime
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Extra: incase you are going to export this to a .exe format, since it is a big game, make sure to export it to electron or nw.js as a 64bit application or else it won't work.
1. Tech Tree: From what you're describing, there's already a tech tree in the game. Just click on the green "r0" in the bottom left corner. It's next to the money/health/oxygen meters.
2. Cloud saves: Not possible. Cloud variables in Scratch are actually more like servers than databases, so if you save your game to the cloud, then other people could access your save. Even if it was a database, Scratch's cloud variable limit is 256 characters, and a Colonizer X save code is well over 80,000.
3. Achievements: Those are actually planned, I just don't have them on the updates roadmap. They are indeed coming soon.
Bonus: If you're wondering why the save system is a bit wacky, it's due to some weird bugs with ""words"" that are over 80,000 characters long, that being save codes. I seriously had to revamp some code in order for things to work. I do want to update that, but as of now it is not possible.