I'm now into week 3 of Get In The Ring's development. A friend told me the camera was a bit jerky and pointed me to this excellent article that covers anything and everything about cameras in side-scrollers. For now I've adopted the camera smoothing approach where the camera chases the player position instead of always being centered on it. It helps when the player jumps around to counter enemy attacks.
I've also been implementing a new enemy that grabs the player and leaves him (more) vulnerable to enemy attacks if he doesn't react fast. Gameplay video: