FWIW, it's also my experience that the game doesn't get hard fast enough. In fact, it's a major reason why I haven't been able to really play the beta very much, despite having played the alpha 999999999 times. If I had to choose whether to play the alpha or the beta right now I would absolutely choose the alpha due to difficulty / quicker startup.
>>>What's more boring, an easy run or a run that peters out into nothing as you slowly realise that you're not going to be able to win for whatever reason?
Just add a Resign button. It working that way is WAY better than having the possibility of a mis-click ever prematurely ending a game. Or, it might even be possible to have the system detect when there aren't enough resources to proceed.
>>>Giving up that most basic element of rogue-likes would be like taking the backdrop away from a play.
Desktop Dungeons is not, and never was a "roguelike". It's actually an original game, imagine that. Thinking of it as a roguelike and thinking of it through a roguelike lens is not helpful.
As for whether it's a puzzle (a thing that is solved) or a game (a thing that is won/lost), I would say it's the latter. Yes, there is a single victory condition, but there's a million ways to reach it, many ambiguous choices to make along the way. Actually, I think there might need to be another loss condition present, because death doesn't really make sense.
>>This has nothing to do with DD, and everything to to with the limits of technology. There is no computer command for "you know what I meant to do."
This whole argument is off-base because we can fix the problem by just not letting you kill yourself.
>>>Well, now you know how much mana fireball costs

The feedback issue you talked about actually won't solve the problem. If you're playing a lot, you're going to be playing quickly, and you're going to be used to pressing the fireball hotkey and then clicking. Even if it says SPELL FAILED really big in the center of the screen, you'll still quite likely have clicked.
This is what happens when you have a design flaw, there's like all these emergent flaws that emerge because of it and if you refuse to fix it, you end up having to cover your system in bandaids.
Edit:
THE PROBLEM: Right now, if it says "DEATH",
you don't click. The only time you do is if you mis-clicked. So it does not function for this to be the end-game condition.
Some solutions to the problem:1. Create some OTHER game-end condition. Maybe the mission ends when you reveal a certain % of the map. Maybe there is some other resource. Maybe there's a straight up timer. I don't really have this answer, I just know that death is not the answer.
2. Add randomness to the attacks. If all attacks have some amount of randomness to them, then death can be used, because players can make a risky move. I am actually NOT a fan of this kind of randomness in games, but I prefer it to straight up illogical design properties.
3. (Least favorite, but still a solution) Just let players resign, or have the system detect when there are no moves left - checkmate.