When I came to this game I decided to nitpick something... But gosh, did you make it hard to do so...
This is one of the most (if not the most) polished game(s) I've played in this jam so far. So let's just give it a proper critique...

First of all, the simple attack could have been boring, but this is a perfect example on how much enemies matter for the gameplay. The enemy variations make it fun to play through, while it could have been dull if the enemies weren't this well-made.

The learning curve seemed fair. Each enemy had a fairly long animation before you need to press attack. So even if you met the enemy the first time, you could beat it.
The graphics fitted the the Nokia 3310 pretty well, with some neat animations, which bring the each character to life and make them memorable.

Even though, the boss fight might be well-balanced, it is not that fun to play through the whole game just to let the player retry the boss. I understand this decision, since if this didn't reset, the game would offer less (both fun and playtime). The enemies were polished this well to fight against them, not just to fail them once and somehow survive. However it is really annoying to fail the boss after spending more time on it than beating all 10 enemies.

Overall, you have done a pretty impressive job, it was really fun and felt like a complete game. I really liked it.

I enjoyed this a lot, very fun! I couldn't beat the boss tho :( But everything else is really well done, specially the animations, good job!

I managed to beat it! ^^ Really fun and cool concept! Loved how you did the boss and darkness. Also really cute!~ 

Really cool game! The enemies are varied and interesting, and the boss fight was really well done. I like the concept of having to press just one button, but having to time it well. Good job!

Awesome game! I liked the visuals, music and the different enemies. The sword mechanic sounds repetitive when the game starts (due to the single attack), but when enemies appear it becomes really satisfactory. :)

wow, this is one of the funniest games I've seen so far! Very nice music and cool pixel arts! :-)

I wasn't very good at this game. I couldn't time my attacks properly. I got to the ghosts and that was it for me. The difficulty curve was pretty good though.

I really liked the visual style; you gave the sprites a lot of character despite the restrictions.

Please base your ratings on the Windows version. The web version refuses to stay monophonic for some reason, and there are a bunch more issues regarding the sounds and music.