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.