you already know i love this game and the art in it, so i'll go straight into my thoughts. i wanted to play as Iris since i've played as the previous characters before.
so, i boot up the game and buy Iris. going into the dungeon with her immediately kills you
i resolved this by buying bomb girl, starting, exiting, then starting with Iris.
i immediately noticed more sound and maybe a change in the music? it's very nice.
holding left-mouse-button with cyclops girl makes me use her Idle animation. i can move around as i do this, which looks silly. since i see you're using unity, look into how you should handle animation layers for 2d objects. it's simple enough for 3d, but i figure there's probably something similar for 2D sprites. either that or divide the sprite into halves so you can animate only the legs on movement and only the arms on attacking.
on level up, a bunch of buttons appear to select a powerup. if your mouse is in the middle of the screen, as the buttons appear you technically "mouse over" all of them , playing their sounds. ideally make the colliders for these buttons inactive while the animation plays, and active once its done. this is a very minor thing.
having fireball, mines, helicopter bots, ice aura and thunderstrike is a lot and there are many particle effects playing at the same time. not sure if this is an issue or not, but if you add more skills it might clutter the screen too much. not sure what to do about that, it's just an observation anyway.
for the spider-mines, consider making them auto-deployable. it might be interesting to have a character that doesn't need to attack, the robots automatically do it for her! it fits her style anyway, since she's shown with her hands in her pocket, like she doesn't have to do any more work.
text stuff:
couple of typos i noticed. i wasn't paying that much attention but these are simple
>Allow Iris too deploy spider bombs -> Allow Iris *to* deploy..
>Rise your X Y Z -> Increase your X Y Z. Rise is to get out of bed and "Raise" is to increase something, but just saying Increase sounds better
Leveling up the Aerial bomb says it increases by 1 up to 3. i first understood that as "you will have 3 after this upgrade" and i was confused, but i found out you meant the Maximum possible amount of bots is 3. if this is the case, you should not write that and instead simply not allow the skill to show up again on level up.
as always, great stuff. the game is progressing nicely and improving every DD. keep it up!