My very first impression was that the water animation on the start screen was crazy impressive. All the special effects for the characters were really impressive. Some of them needed tuning for game feel, but for looks they were top notch. Also, all four characters look great. Did you make them all yourself? They look professional.
I happened to have a group of 9 year old boys walk behind me while I played and they all really liked the look of the Battle Mage in particular.
Others have already mentioned the camera controls and I saw a reply that you know it's an issue. I do want to reiterate that solving the camera issues is the most important thing you can do next. The floaty, unintuitive controls were giving me motion sickness and I still feel queasy. I also really struggled with the jumping with the camera and never made it to the end of the level with any of the characters.
When I tried the gunner, most of her skills didn't seem to shoot anything and her animation had her move her gun to the side. Just maybe a bug to keep an eye out for.
The last note would be I would love to have a hint (doesn't need much at all) of what the intent of the game is. Is there a story going to be connected to these characters someday? The title screen seemed to imply there might be, but the level felt like a tech demo with no particular purpose beside testing out the characters. It's fine either way, but I think a little clarity there could make a big impact.