My drawing looks unfinished but i don't really know why

[random turret]

I can only guess theres not enough gradient or highlight and if that's the case im a bit lost on where or why it will work

[spare osprey]

Hmmm I really like this art piece! The colors are really pretty and it just looks super cool! I’m no expert, but maybe if you had less of a simple background it may look better to you! I’m not sure tho so maybe experiment a bit!

[exotic depot]

I think adding some texture would be cool, looks phenomenal as it is tho

[candid thicket]

A signature can fill in some of the blank space 🤷

[random turret]

ooo the wall, havent thought of that but after a second look it might help seperate the planes, thanks

[random turret]

i adjusted the background and added some random baloons so it looks less empty

[spare osprey]

Oooh that looks rlly cool!!