I found the gameplay pretty addictive! Played for about 20 waves. I noticed that the game becomes a bit easier after some time because of the sheer amount of towers you're able to build.
One thing that I enjoyed so much was the fact that after setting up my plants, I could use one type of plant as a weapon to fight the waves as well. This made the game so dynamic that I was never bored (which may happen in certain kinds of Tower Defense games)
More types of enemies and of course, sound/music would be really great, but the game is already very enjoyable as is.
Here's a pic of my garden haha (I had a lot of towers at the edges as well).
Good job!