Edge of Space is not a great game, I'll just put that out there. In its current state, the interface is clunky and confusing, the initial spate of gameplay is repetative and your objectives are unclear. If you're looking for something on par with Terraria, you'll be disappointed.
Why, then, do I recommend Edge of Space?
Because, beneath its rough and unpolished exterior, lies a surprisingly fun and enjoyable experience. The gameplay, while flawed, is enjoyable. Crafting schematics and unlocking new content is fun, although grinding for materials can be tedious at times. The art and sound design is gorgeous (actually better than Terraria, in my opinion). The devs are responsive and listen to community feedback. Updates are regular and often (in fact there's even a timer so you know when each update is coming!).
Edge of Space is a quickly evolving game and, while, it may be no Terraria it's going places. If you're looking for a polished product, you may want to wait a while before purchasing this one. However, if you're willing to put up with the bumps along the way, I think you'll find Edge of Space is definitely worth playing.
Edit: Wow a reply from one of the devs!
I'll address a few of the things here. My biggest problems with the interface are fairly small things, organizing the inventory can be a pain, how to remove/add background blocks was not well explained and threw me off for a while, and when clicking from another window back to Edge of Space I often end up accidently placing blocks I did not intend to place.
As for repetitive gameplay, I feel that early in the game certain crafting requirements are just too high. For example 20-40 biomass to craft certain items. Biomass can be difficult to get in large quantities early in the game, meaning you have to grind for it.
As for long term, I'd like to see more variety in enemies, there just doesn't feel like much variety. I'd also like to see more customization options implemented, dyes, paints, etc. More weapons and variety of weapons would also be nice as it's hard to find a weapon that suits my play style.
Overall I am very impressed and thank the devs for replying to my review! :)