Can't figure out if there's anything to change before doing lineart

https://preview.redd.it/oizq35jljvrh1.png?width=502&format=png&auto=webp&s=d232058cb47fbd8064a08b4f71486a81d10b790c

I'm currently trying out a new drawing method called colored sketches (Self explanatory), though after what I believed was finishing the sketch, I realized something felt off, I want to fix anything weird before doing lineart, anything I should change? (Except for the size of the gun, that I know is too small probably..)

Please don't hold back any critique even if its harsh, I haven't made any major art piece in months and I need to make sure I make one and I make it good.