You're asking the developer to tackle a significant alteration to the game design as a result of a perfectly-fair challenge that might trip some players up ONCE, TOPS, if they're, you know, actually learning the game. And yes, it's an alteration. I mentioned this elsewhere - shields are NOT a way to prevent that "already", and I'll explain why: shields stop you from doing something potentially suicidal on YOUR turn due to enemy attack ranges at that moment, based on your attempt to move or not move. If you've destroyed an interposed piece and opened yourself to attack, it's now THEIR turn. It's too late for a shield. You had your chance to not be careless with a firearm [there's a life lesson in there, but I digress] and you reaped what you sowed. For a shield to stop that, the game would need to have a far more complicated mechanism that looks at what you're shooting at and calculating every possible combination of destroyed piece resulting from it, and then trigger a shield if there's the slightest chance any of those combinations could be lethal. If the dev wants to do that, more power to them - it'd be nice for me to not have to burn through shields before taking a shot 100% guaranteed to result in my survival despite sitting in an attack range (which is how I know the game doesn't currently calculate potential damage dealt when shields trigger). But if I were them, I'd remove shields from the game entirely before I'd even think of doing that! The player is the gamemaker's apprentice, and if they stop learning due to overdependence on the training wheels, then the wheels need to go.
Besides, needing to see the consequences of your moves in advance is part and parcel of chess - why should this game be any different? Frankly, I find it alarming how many people are complaining here about losing a game because of a mistake they made, demanding the game be changed to prevent that mistake (especially those that know losing that way is fair). It's like they don't even know what "game" means. Chess is already super polite in preventing someone moving into check (which I assume is why this game has shields in the first place); try going on a chess forum and suggesting the rules of chess be altered, with moving into ANY mate-in-one being similarly prevented. See where that gets you. But that's literally the non-digital version of what you're asking for. Feel silly yet?
If chess itself isn't up someone's alley, I don't know why they'd be hanging around here at all. It's not like there aren't several thousand other roguelikes out there. Heck, this same dev has another.
As for your comments on "practice", two things: first, "not being oblivious" isn't the sort of thing to which "practice" really applies; second, the entire arcade-game generation would like a word about what you think "practice" entails. Starting another run IS practice. To imply otherwise is so far beyond my comprehension not just of roguelikes but ALL games of all types, digital and otherwise, that I can't respond at all. For that reason, I'll be taking my leave of this conversation now. I hope what I was able to respond to has been educational.