An interesting take on linear algebra (but without requiring the player to have any technical knowledge). It is fun and challenging!
The final part of the finale is ... interesting. I would have put it in the second last level as an interlude, but this is just personal preference.

Hi, I have played a few rounds. I am not very good at this.
I have a few things in mind:

1. Like the simple art style.

2. It is nice to have a leaderboard (btw, I got 179), it motivates me to play a few more rounds.

3. The lose condition is not very clear. The shape of the wave makes it hard to get the exact lava level. For most games (e.g. platformer) this does not matter, but for a game that requires precision, it is better to have some sort of indicators.

4. After starting the game, there is nothing to do for the first few seconds, because the player has to wait until the blocks are near the grounds. This is ... a bit boring, especially for a game that is supposed to be played multiple times.

5. Sometimes it is quite frustrating to play. If the "character" hit a wall/jump then stay, the player has no control over the "character" until it hits the ground. Will you consider some ways to recover? (e.g. Still able to press the down button to go down faster)

[EDIT 14 July]
I have tried playing after the update. It is much better because the player has more control over the game. Even though I am not very good at this game (I got stuck easily), it is still fun to play with.