This game looks and feels very good, from the moody graphics to the screenshakes when you take over the host cells I can tell that you've put a lot of work in to it.
Adding sound to the game could surely improve how this game feels by a long stretch often you can find good sounds on freesounds.org, another place I've come across is a large pack of sounds I saw released on r/gamedev from the GDC (think there was one pack with 10gb and another with 16, so there should be a lot of variety). Just make sure you find sounds that are distributed under the creative commons 0 license (free to use commercially, as long as they're not sold as is)
Another minor thing that I feel would improve the feel of it would be if the button in the lower right corner turned on camera follow untill you clicked it again, instead of turning off the next time you move as it does currently. This way the camera could keep following you around as you moved.