Hahaha it's so much fun :D Please tell me you were secretly working on next 50 levels so I can play it more :P
Theme:
Wonderful attempt to catch the theme in it's fullest. Definitely you can feel that game gets significantly harder with many bugs (it doesn't mean it's less fun tho :P i've loved smashing my keyboard and spamming all kinds of attacks).
Visuals:
They are great, bugs are lovely, UI is for sure the best I've seen on this jam and you really tried to get as much from it as possible (I love Bob!). From what I've noticed, you made a great use of particles, but they die instantly, which makes them look a bit unnatural (I know it's a small detail, but many details like that can make player search for mistakes, and we don't want this creating a game), so I would recommend setting SizeOverLifetime to curve that goes to 0 at the end, or setting ColorOverLifetime alpha go to 0. It should make blending of those effects a bit better.
Also it would be good if you've indicated that bugs were killed. You can do that by doing some simple puff particle on them or for instance creating a sprite variant with 'X' instead of eyes with a bit blanked color and disappearing by scaling size overlifetime, it might look pretty good ( I can be mistaken tho).
The last problem I had was with placing towers. It was hard for me to estimate where I can put my cute bug and where not and it made me a bit confused at some moments, especially when I wanted to place a bug during the wave and I couldn't place it. (would be also good to have 'back' button, so you can easily go back to playing without placing anything)
Innovation:
I'm a big fan of Tower Defense games and I've seen many amazing entries on the past jams, like having tower defense on your keyboard etc, but your's is something else xD I'm waiting for steam release, no excuses :P
SFX:
Sounds are really cute and well fitting, music on the other hand is also good, however same problem as with particles. If you could blend it a bit more, make some transitions so it's smoother then it would be an amazing piece to play to!
Gameplay:
Oh loved it, just not enough levels :P (enough for gamejam, but I'm hungry for more!). Game has a great potential to build upon, lovely atmosphere and artstyle that would definitely fit many peoples needs (there are many tower defenses like: Kingdom Rush or Anomaly that are a bit harder on the way they are made) as it's really friendly and feels really positive (It even has a lot of room for pretty good plot :P)
Game Design:
Amazing job on leading the player. Menu is so wholesome and fascinating. You give information in a very pleasant way and teach the player how to play before he even enters the game, that's very good idea. Game itself gets harder with every level pretty well. Maybe I felt a bit too strong on last couple of levels where I just had enough money to demolish any wave, but it's the matter of creating other enemy types etc. (Boss would be good). 'Kingdom Rush' is a great reference for that, they have used so many connections between towers and monsters that it's a great base to learn from.
And it's also good to reward the player after he beats entire game, even with simple art of happy ants or anything :P (Actually I was so overwhelmed by your game that I didn't feel the need for that, but it's useful to have).
THANK YOU! Don't dissapoint me with next levels xD