Dark mode has too much contrast and is too dark for real use, you need to make the black into a dark grey and the white into a very light grey. Also game just continually crashes, probably because of the skip floor thing
add-ons for my previous comment: healing should also have a clause to check if the enemies will kill a member of the party before their next chance to heal, and if they will, will their heal change that. Another benefit to the RTA style instead of the current slow turn based is that if your damage is too low right now, it's much slower to do higher floors even with the increased reward (changing the scaling should also fix this though)
Simple dark mode colour base: black text = #eeeeee, backgrounds = 2f2f2f
Other coloured text (like your red) just lower the colour values to be closer to 0, instead of #ff0000 for your red, make it #990000, etc. This won't be a perfect result but it's fast and easy. (you can get a hex colour converted on google if you are using a different method of selecting your colours)
Healing AI should be able to do basic maths to see the value of healing. a basic AI would be if(can kill enemy) kill enemy, else if (hero HP+heal power > hero max HP*1.1) heal, else attack. super simple, should work for most things.
The healing AI is actually a little more complex than this. Although I improved it a little further after your reaction. Of course it uses basic math. It uses the total team healing amount, the armor reduction from your first alive hero and scales the importance of healing based on how many other characters would attack. While sometimes it might seem as if it should heal but it doesn't, this should mostly be because it wouldn't help the first hero survive, and dieing is better for your progress in this case. In other cases it might attack when you'd think healing makes more sense. This should be because reducing enemy damage would make a better chance at survival later on. Anyway, it might still get better, but I hope this clarifies the logic a bit!
Increase the Double rate of power from 1 floor to a higher number, like 10. This slows down the harsh scaling, allowing players to take advantage of the higher exp for higher floors, making the start at floor - 10 bonus much more useful, and increases the utility of max HP and healing, as currently the best strategy is just max defense first hero and 2 max damage heros, any enemy that can get past your defense one shots you for the most part, with a slower scaling that wouldn't be the case.
change the game to be more RTA than turn based, so all characters on the screen charge their attacks at once, this greatly increases the game speed. you can also add a speed stat to determine how fast this charge goes if you wish. the game currently runs very slowly so some increase to the base speed would be greatly appreciated.
The "Kill multiple enemies at once" thing is so over corrected I spend the majority of my run fighting early enemies or complaining that I can't buy multiple levels of the final weapons in 1 click
Known bug, will try to fix in next update.