Quite enjoyable game, but not without problems.
I like the style – nice art, catchy music, the sounds are okay. It's an action game rather than a platformer because your movement is rather slow (in comparison with other platformers), so this is not a game which should require you to make complicated jumps or react quickly – which shows the most in the boss arena (trying to quickly jump between platforms, or jumping from the edge of one isn't exactly the simplest task).
Slowing down the player when you charge (or hold) a big fireball is the right decision, but in my opinion, shooting small fireballs shouldn't slow you down at all. That makes shooting while jumping more difficult than it has to be.
I feel like there's a slight problem with pacing – the beginning is okay, the end boss is hard, but the middle part starts getting boring after a while. Occasionally, a new enemy gets thrown in, but the difficulty doesn't really change. I remember thinking "how long will this keep going yet?" roughly in the middle.
I don't know about the crystals. First, if you right-click, you shoot all at once for the number of crystals you have – not just one per right-click (completely unnecessary for every enemy except the boss).
Obviously, you want to save the crystals for the boss battle, but during my three playthroughs, I always managed to die on my first attempt – which means all of the crystals are gone. Perhaps save the current amount of crystals when you pass the checkpoint, so when you die, you only lose the crystals in the current section? Otherwise, I don't see much point in collecting them.
As for the pixel art, I noticed the pixel size isn't consistent. Sparks from the crystals and the flames are smaller than the individual pixels in the walls. Then the "charging" panel and boss's health have round edges and the ball of fire returning you a safe location isn't pixelated either.
It's not *wrong* to have an art style like this, it's just not what some would call ‘true’ pixel art.
Also to me, the solid black tunnel at first looked like an entrance to another location because there was no door nor a portcullis to block it.
And after defeating the boss, the game promptly kicks you back to the menu as soon as you leave the area. That is the video game equivalent of "Fuck you". Add a final, 'reward' chamber, or at the very least show an ending screen. It took some effort to get to the end – but you don't celebrate the victory.
That's like meeting the person who won a race and being like, ‘Okay. See you next time.’
Uh, and you also got in one of the most common problems with Unity games on this site – if you use "Standard" WebGL template instead of "Minimal", you have to add 38 to the vertical resolution of your game in Project System for the footer, otherwise, your game gets cut off slightly.
And since this is Unity, you could potentially save the player's progress between playthroughs in PlayerPrefs if you wanted. I. e. adding a Continue button to the menu. Just for convenience sake, but this game isn't that long to make it a necessity.
But overall, I think it is a pretty good game.