I like it. Nice game mechanic, I already get many idea how that can be expanded. I thought at first when we got hit, the sword will change color like HP usually change color every time you get damage, after the color turn red then it will drop, so you have maybe 1 to 3 hit before the weapon drop.
A few bug that enemy will not spawn after you restart or enemy can get stuck and don't move. And I don't know if this intended, when the sword drop and enemy touch the sword, the enemy get damage. If that intended, that can be expanded too.