I really enjoyed playing this! I think with a little more variety in the enemies, a tower upgrade system, and maybe a mode where the enemies don't stop and just get more numerous steadily would be great! I did run into an issue once I got to wave 14, where there are so many sfx playing that it glitches out the sound and it stop playing for a second or so, this got worse and worse to the point where I am stopping playing at wave 30 because even the music is skipping back and forth now due to the overlapping sfx. BUT, GREAT game, would easily spend £10-£15 on this depending on how much depth you decide to put into it! Ultimately, it is your baby, and your vision. 
Thank you so much for playing! I definitely plan on adding more content & fixing up some mechanics, and then putting it up for like a few bucks on Steam & itch. Thanks for the feedback! Also with the SFX, you can pause the game and turn the SFX down, it’s probably just some issue with the game running in the browser.