I just lost my entire response due to the screen refreshing, so I'll try to remember what I added.

The main points were that you have all the right ingredients, however they don't exactly mix together well. Also, ideas aren't properly conveyed in the design of certain aspects. Try to keep in mind methods of displaying the function of game objects to the player, as non-intrusively as you can. 

1. You have fast player movement (which I do heavily enjoy), however the levels are cramped and small. Zooming the camera out, or increasing the size of the levels and adding some verticality to them would be an amazing addition.

2. The function of the flame traps was not obvious until I stood still watching them. Maybe add a flame symbol to the front of them, or some particle effects while they idle.

3. The time difference from damaging an enemy (by clicking), and when the sword finally reaches the enemy is vast. The enemy is already dead before I visually strike them. One possible solution would be to keep the sword in the "pulled back" position while running, so that the moment you click the mouse button, the sword can immediately go flying through the air.

4. Just 3 small bugs I noticed:

• The button component on the pause screen for the music option is not properly stretched. I can click pretty much anywhere on the word "MUSIC" without the option changing.
• The "RESUME" button does not unpause the game.
• The flame traps would sometimes not reset when dying. They would continue to stay red when I would encounter them again.

5. The checkered blocks between each section in the level seem to serve no purpose. The flags act as save points, but the blocks of the same material don't seem to do anything? If they are to function just as an indicator that you have finished that section in the level, then I would recommend using something else in place of them- if anything at all. The "walls" going straight down from the roof already act as good separators.

Overall I do believe you're most definitely heading in the right direction, but you mainly just need to convey your message/ideas a little better. One more example of that, is the hamster is a dragon and has wings, however it can't fly nor shoot fire; but the enemies are knights with swords, and some of them can shoot fire. Just tweaking the design of certain aspects of the game would really give it a massive boost. If you have any other questions or anything of the sort, feel free to let me know and I would be happy to continue helping! Also do make a post when you update your game. I would be glad to continue giving feedback on this project.