I'm both an impulse buy and also (I think) your primary audience, as someone who's played Nethack, Dungeons of Dredmor, DCSS, Darkest Dungeon, FTL, Dwarf Fortress, Project Zomboid, The Escapists, Atom Zombie Smasher, etc. (forgive me for assuming I know what your audience is - I'm guessing). What I mean by impulse purchase is that, having made the decision to purchase it, I want to go quickly from making that decision to having the game in my hands. This is one area of user experience where Steam really excels. This includes assessing the risk of making an alpha purchase. Once I figured out how to purchase, your system that emailed me a download link delivered. :-)

But yes, I understand what you mean about discouraging random people who stumble across it from not knowing what they're getting into. Early access games are a phenomenon these days from Steam however, so a lot of people are familiar with the idea and comfortable with the purchase being a gamble, especially when the developer is making an effort to engage with the community, and you have a sense that the game will continue to be improved over time. (I am really looking forward to Terraria 1.3 for example, and find it amazing and delightful that Re-Logic continues to add so much content. They've already secured my purchase of Terraria:OtherWorld.) I also understand that it wouldn't be fun to have a bunch of unsatisfied people harassing you and consuming your time with returns. Just sharing my thoughts as someone who saw the demo and thought "I want this NOW" :-)

The level of polish in the video, in overall slickness and animation and sound effects, gave me a good sense of what I was getting into, and I can say from the game's "loading" screen, first level, animation & sound effects, and interface polish (including item & effect descriptions) I am not at all disappointed. It's great!

I like the fact that you've put a lot of effort into making the game playable without a reference, with inline help. A lot of other games fall down there, including AAA titles.

I haven't played more than a few minutes, so I don't know if by unfinished you mean you need to add a lot of content, or you mean the game isn't playable from start to finish. If it's playable from start to finish then I'd say you're in good shape (if not, then that's understandable as an alpha, and I agree with keeping it away from the mainstream until then). If you mean you can finish the game, but there isn't as much content as you'd like, then I'm sure you will improve it! One thing I'll be interested to see is whether the item drops result in a character that plays in a way that "feels" different, e.g., legs vs. wheels. Movement taking different amounts of time is something that I can grasp as a roguelike player, but I think items will offer the most variety if they can "feel" different somehow (that's the best I can describe it). FTL teleporters and stealth are an example of items that drastically change the feel, leading to completely different gameplay. Project Zomboid melee weapons vs. firearms is another example. (With wheels, can I effectively roll up and melee things when I couldn't on legs? I would hope to find tactics like this.) It's the emergent gameplay that makes tactical games or games with sandbox elements so beautiful and interesting.

Thanks for posting! Good luck!