Hello ! Thank you so much for the detailed feedback, it really helps!
All four points have actually been fixed in a major update that just dropped:
Game loop : The game is a wave survival mode, you fight endless waves with increasing difficulty. The goal and scenario are now explained in the page description!
Hitting from the right : The hitbox flipping issue has been fixed, you can now hit enemies from both sides.
Getting stuck : Enemies no longer block the player's movement, you can always push through them.
Dead enemy animation : This has been patched, dead enemies no longer play the attack animation.
Feel free to give it another try, and thanks again for taking the time to play and comment !
IMPORTANT : For the best gaming experience, I recommend playing the game in full-screen mode.