Making the art style consistent was definitely a struggle and there were some things that feel off (like the dithering). it's funny that you mention having tufts of grass/flowers because that was what I originally was doing, but felt it didn't look quite as clean.
I definitely tried to keep gameplay as simple and easy to jump in as possible, so I'm glad that the game had that feeling for you. I DID try to emphasize the importance of micro management and multitasking, Even to the point where I kept in the ability to use the scythe while also watering plants instead of making them exclusive actions.
The blue bars under plants are their saturation meter, which increases their growth if it is filled, but will drop over time if they aren't being watered. Max saturation doesn't do anything significant other than to just let you know your plants have water. When their saturation bar is at 0, they slowly lose their orange bar over time(even if not being attacked), which is HP/growth. You can only harvest crops in the 3rd stage (the goofy blue headed plant dudes) and harvesting them gives you points and cash, which can be used to get a higher end score as well as buy upgrades, respectively. You can also get points and cash by killing worms alone, but doing both harvesting and killing is optimal, as you won't have enough money saved from just killing by the time the difficulty starts to ramp up. It kind of adds to the micromanagement as well as the risk-reward of "do I keep more plants alive for longevity or do I harvest them all in a risky move to earn more points?". At least, that's how I saw it.
There's a bit more to upgrades that I could be more transparent about, but couldn't find a good way to show what they did in-game and didn't want to clutter the itch page with all of what they do. Scythe is mainly damage increase and cooldown decrease, however plants and the watering can have multiple unique features. Some of them I couldn't get to work by the deadline though, unfortunately :( I actually wanted to make it so plants shoot projectiles at level 5 that increase in power and speed each level after that, but I couldn't implement it properly with my limited knowledge.
Thank you for all of the great feedback!