First of all, I'm glad you think it has potential and thanks for all the feedback.
Yes, bugs, I know they're annoying, not just to experience but also to fix. As this is just an amateur's first game my philosophy so far has just been, 'as long as you can make it to the end without a headache, it's good enough for me.' I focus on the stuff I like to do, otherwise there wouldn't be much point in doing it.
Same with menus and menuing, yes, a lot of it could be better implemented, but UI design isn't interesting even if it is important.
The inconsistencies in art are a combination of inexperience and laziness. Some of the older art and sprites do not fit in with the new stuff, but redoing all of it over and over again would take too much time and I'd rather just keep moving forward. I'm personally quite fond of leaving the older, uglier stuff in because it feels likes markers of my own progress and improvement. Might not be the smartest thing anyone's ever done while making a game, but this is a learning experience for me.
Predator enemies is a possibility but only as a game-over type thing.
Whole new outfits and things would probably only be added if I ever finished the game. Making entire new spritesheets is not something I'd look forward to.
Sorry if I didn't answer everything you wanted and also for the late reply. I was away from home and couldn't log into my account.
I do hope you continue to enjoy the game.