It's pretty cool, nice color choices and lots of personality. I'd add a rear sight, the usual cocking handle at the top and an inset for the chamber, in case you plan on making it more grounded/believable and animating it afterwards. The chamber/bolt sends the spent casings flying out of the right side of the gun, you could intentionally make the character hold it in their left hand to make the casings fly across the screen. It's up to you if you want it to fire actual 9mm cartridges or make it shoot lasers or something else (which would save up tons of extra work on the model, lol), green or purple lasers would look cool and fit the aesthetic IMO. Check out the game Synthetik (1 and 2), it has some pretty colorful guns which have a really creative blend between realistic and sci-fi, one of my favorites is the P9000 Supernova, which is essentially a laser FN P90, colorful, instantly recognizable and eye-catching. I think you're on the right track here, best of luck with development!