Interesting idea to be able to collect water and watering plants to make more locations reachable. :)
However, having no way to heal and/or save progress is too punishing, because it effectively means that 5 HP you start with are all there is. On the other hand, you get huge amounts of water (I guess mostly from enemies).
There are a few bugs. It seems like slug enemies completely ignore gravity, just moving to the player horizontally when the player is sufficiently close and returning when that is no longer the case. Scorpion enemies take damage inconsistently and seem to fire their projectiles proportionally to the distance of the player, which can get too fast if they fire them from a large distance (I guess they were programmed to travel from source (scorpion enemy) to target (player position at the time of shooting) in a way that their position is a linear interpolation between source and target, parametrized with the elapsed time).
Third type of enemies (mosquito) seems to be fine.
Despite no save/no heal, I managed reach both dead ends and did not feel a need to use the shovel (L, dig key). It seems like it is better to just avoid the enemies most of the time.
Graphics and music are nice. Melody sounds familiar. It would be nice if there were more sound effects (I think I only heard anything besides the music when taking damage).