Having seen the trailer and not downloading yet I'll give you my first impressions of what I've seen.
First and foremost is that it doesn't look like a game that I would want to play. This is because it looks very generic like the characters were purchased from a site. The trailer doesn't highlight effectively what is exciting about the game. It takes a while to get to game play and the game play presented doesn't look fun and is held too long instead of conveying the message of what you do then highlighting the next thing. The games aesthetic also seems to be all over the place, I saw roman soldiers, gangsters, and robots but that doesn't seem to have an underlying theme to them. The game play looks cheap as well, I saw enemies moving really fast back and forth in a platforming section and it just felt silly.
Ok I'll stop there for negatives because I don't think that's fair and isn't constructive. What I think you can do is celebrate that you finished a game and shipped it, that's hard no matter the project.
Here's some things you can do to improve yourself.
I would say to focus in on a main game play mechanic and to polish that to high quality rather than pushing for multiple game types. If you are using purchased assets I would say those are good for prototyping but try to find someone to work with on art. If you are doing art I would say find a style that's not realistic since it's really hard for a small project and will get a lot of flak from an audience if it isn't great.
Congrats on finishing your game and releasing it, and good luck on your future games. I'll download it and if I have any other feed back I'll post it here.