I really Enjoy iy :D

Considering this is a tech demo, the principle is actually quite nice. Reminds me of Bit Trip Runner.

Of course, in the finished product it would be nice to have a greater variety of obsctacles, to randomize things a bit... and most importantly, to add a difficulty mechanic. Unless you play for the game to have a proper end, the game must have a mechanic that make the game eventually end.

Likewise, an interesting mechanic for endless games is having an unlockable animation/ending sequence varying on how far you made it before the game ended.

For the finished product, I suggest you add sound effects. Also, clean up the running animation a bit ; it looks a bit awkward. The warning arrows are a nice touch as is the boss weakness indicator at the start of the fight.

Graphics aren't especially impressive but I liked the general design of the opponents and the ways to dispatch them.

As a whole, I encourage you to keep going with this project.

The controls are awful and with that jump animation I'm never sure if I'm going to clear an obstacle. If you're going to make me hit weak spots with specific jumps then make the jump controls more solid.