Well, it's a neat concept, but even as a demo, it's woefully scattered. I'll try to give you a really concise, bulleted list since you seem to actually be reading/replying to the reviews:
1. I get that interaction with the player is one of the main ways of keeping them engaged, but it's awful and tedious to have to manually click on literally everything- envelopes, items, selling, crafting. Looting shouldn't be a chore, that's supposed to be the "reward" for doing other tedious tasks.
2. Lack of guidance. Specifically regarding the dungeon. I sat around the first level for 15 minutes trying to figure out how to go home before eventually getting an escape rope from a mid-dungeon shop.
3. Envelopes. Your minigame inside a game was a neat little thing for me to spend 5 minutes getting good at, and then summarily being frustrated about having to learn in the first place. Five minutes in the dungeon makes it apparent that envelopes are a waste of time and the only reason one might ever need to make use of them is if all of their cubes die. A much more streamlined mechanic would be to just make adoption free with a smallish cooldown timer so you couldn't adopt over and over for a perfect cube. The envelopes, unless made integral to the natural progression of the game, need to go.
4. Lack of party options. Why can't I re-order my party in the dungeon? I shouldn't have to waste an escape rope if I decide a floor in that my main and my assist should switch places. Secondary to that, if I bring two "main" cubes, why can't I bench one of them? It's clear that health is an important issue, so why should I have to watch my cube slowly die in front of me when I have two perfectly healthy assist cubes hangin' out doing nothing on the sidelines? And why can't I switch mid-dungeon to just using one main cube?
5. Crafting. I had no idea for the first half hour that crafting the same item twice could result in different stats. I was also just barking at the wind trying to figure out what went with what to craft what- and further, what on earth crafting level did, since it didn't appear to make individually crafted items better.
6. Theme vs. Outcome. This is a preference issue I have, and others may not share it, but it makes me scratch my head to see a pair of sunglasses contributing anything to attack, defense, or speed. Same with the rest of the items. I realize that cubes don't really have the appendages to wear boots or wield swords, but maybe you could incorporate different theming so that it's a little more sensible? Like crafting other cubes into a weapon that attaches to your cube. I don't know what substance they're made of, but if it's slime, break a cube down into a slime axe or something- not that that makes a whole lot more sense, since the cubes are shooting weird lasers or something. Point is: it comes off like a dress-up game where stats are arbitrarily attributed to the costume pieces in a fashion that has no basis in logic.
7. The cube powers are pretty cool. Why can't I know anything about the power they use until after I take it into the dungeon? (It seems like it might be color-based, but I don't know that after an hour of gameplay, so it's a moot point unless I'm told from the getgo.)
8. Scattered. So, you're going for something unique, which I get, but in the process, you dabble a bit in pet simulator, life simulator, rpg, dungeon crawler, crafting game - but you don't really hit hard on any of the points. I enjoy the combat system, though it gets stale after a while- but other than that, everything feels like the start of an idea for a totally different game that you mashed all into one.
9. Bullets. Why does my character have a gun, why does that gun heal my cube or spawn platforms of all things, and what necessitates this mechanic being separate from the standard inventory? Why not just make it so you can hotkey certain inventory items and use them mid-combat for certain effects? Bullets are confusing mechanically and thematically as an addition.
10. I understand that this is just a demo, but without knowing what your plans are for the dungeon's layout, holy stuff is it bland. It's the stuff of dungeon crawling cliche nightmares- I can the same 3 enemies, see an empty room, a room with one or two crates, or occasionally one of four or so scripted rooms that function to serve me in some way. This goes back to picking a direction and sticking with it. The resources wasted developing the envelope game could have gone into making the dungeon something other than a repetitive slog.
11. Why the main character? Is there really a role the main character plays? If these robots are the size of the cubes, why am I not stepping on them or hitting them with a baseball bat? I feel like the game would be more streamlined if you just took control of the cubes yourself. As a little aside on top of the need to have human elements in this game, what's with flying to California? (And why is it free?)
I say none of this to discourage you, but I'm not sure something like this is ready for kickstarter. I think you should pick a direction and really push in that direction without getting distracted by mechanics that you want to design, but don't really fit with the game.
Good luck~