A lot of cool ideas ! Totally made sense to make a VS-like game and it is globally well implemented.
As someone mentionned I a had some trouble with the readbility, mainly from the enemies disappearing and not always knowing if there were dead or not. The damage counter appearing on top them is not that useful since they your sprites are their own healthbar and made me think that the aoe rotating erasers were doing no damage.
I also often forgot about grenades, spending my collectibles and leaving to next level. Since there is so much thing going on the screen it's hard to track those counters while clicking everywhere. Maybe audio feedback would been better put on this kind of things than on the enemies. The enemy sound was a bit agressive to be heard so much and so often.
Clicking around caused some problems to me as well, I wonder if making the grenades and clicked eraser automatically trigger on cooldown in the mouse direction instead of triggering on click would have made a smoother experience.
Still I enjoyed your game a lot, this is working really fine mechanically. There are cool ideas like grenades erasing the ground and I love the sketch menu.