I wasn't going to review until I saw how awesome the creator was responding to each review.
First off, I'd like to say that you seem very genuine in your replies and thankful for all the reviews, so I tip my hat to you there, and gave you an extra half star for that.

For the game itself I would like to recommend a few simple changes that may make it more enjoyable.

1. Make the meaning behind capturing the candles more clear.
Currently after capturing a candle your snow(point2) regenerates faster. This is okay, but it isn't presented in an obvious manner. Plus with the level switching it was hard to tell if it carried over or not.
2. Make the character and enemies slightly more detailed.
After reading your responses to other people I know Cyoses you're keen to keep the art simple, however it is impossible to tell that your bullet is snow, and I have no idea what your character is.
3. Make things more juicy.
This is something that companies do all the time most people don't realize. Take a look at Mario, the vertical slice of Mario is running and jumping, so that has to be FUN. So how did they do it? They made him have a cool run animation, a great jump sound, a sound effect when he jumps and another when he lands, and in later installments a particle effect of dust kicking up when he lands.
To make yours more juicy could be simple, a snow particle when he moves? An awesome sound effect when he takes over a candle? Platforms covered in snow for a while wherever he walks?
Something to indicate that he has more power when taking over a candle? Whatever you do, just make the vertical slice better.
4. Do more with the idle aspect.
At the moment this is NOT an idle game in the slightest, if anything it's "ugh I took a hit let me wait 10 seconds before I heal" and that's it. What I would do is make an over-world that's constantly generating snow biased on the amount of candles you own which you can then spend on upgrades to your speed, rate of fire, more health, rate of recharge(taking this away from the current capture mechanic), cosmetic upgrades like hats and colors, that kind of thing. Then make the levels much harder or even impossible without some upgrades (like a doublejump?) and if you fail a level you do not get to keep a levels candles, and may even lose more on other levels prompting both the idle aspect and replaying old levels.

That's all from me for now, best of luck to you Cyoses. Feel free to message me if you have any questions or comments or anything like that, and I hope this review was helpful for you.

Keep up the good work,
TheHat.

My first thought was how irritatingly slow and floaty the physics are, but I finished it, and I had fun. it's nothing amazing but I dig the simple rounded square pixel art. fix the physics and add more content, and let me know where to play it.

It's just a demo, I know, but still. It's a bit too simple even. And where is the "idle" element? Was the idle element waiting 10 seconds to get a hitpoint back?
The controls are floaty and environment's hitboxes not very clear.

Overall, doesn't have anything new or different. Demo is way too short to get any feel in the game.

I really wanted to like this game. The mechanics are simple enough and given in a straightforward way and it could have been interesting, but there's no clear motive and then really rapidly into the game I found myself just stuck in a cavern with a giant 'more' button that takes me to your website. Not cool.