This is great! a very very interesting concept, an endless runner with resource managment. I think it's great! Though some feedback:
The jumping is a bit too strong. Id love more projectiles with less impact to have better control of the slime so it doesnt feel unfair, cuz I lose a lot of control otherwise.
I think rather than a wall approaching I'd much rather have a timer that runs out and replenishes the more you move forward, I feel like the wall gives me much less freedom to move with.
Great game!