the bomb plant is really overpowered. you can pretty much clear everything by just spamming the bomb plant all around as long as you have enough money plants in the middle. i suggest making it more similar to the potato mine where it requires a bit of setup time to actually explode on death, or severely nerfing its first stage explosion damage.
Also, the gun plant is really bad, and you pretty much can't make much progress without the overpowered bomb plant. i would like it if you had an upgrade option for the gun plant, like maybe unlocking an upgraded version near the unlocking of the bomb plant where if you drag another gun plant on top it becomes a stronger one (maybe sniper or smg plant) after a regrowing phase (essentially makes it so upgrading takes time so you can't just upgrade them all at once (you'll have no defense if you do)) and it could be a whole upgrade tree like the gatling pea in pvz.
anyway the game is rlly cool other than the balancing related stuff. like the other guy said, its a bit slow, adding a speed up option would be nice. maybe after killing the first few enemies you unlock the speed up feature (like bloons tower defense, you can put the game on 2x speed and slow it back down to 1x)
also i like the designs they are very cute (i don't think you used generative ai but if you did make sure to clarify) but i think the potato rocket could use a bit of extra flare cus hes kinda bland especially compared to all the other plants