I like the idea, it's a cool take on the tower defense genre.
Sadly, no sounds or music! :(
I think the biggest issue right now is that the game feels a bit "solvable". It feels like there's never any reason to pick a fairy - they die really quickly and their speed isn't really too much of an asset, given how the best strategy is to bunch up your units. You need to send them way later than your other units, point by which they're probably vulnerable to the turrets your other guys have already passed through.
It would be very nice to have some more content and randomness in the cards. Because you don't want fairies, you don't see the social media towers too much. This could be partially solved by making the cards select a random buff and a random debuff when presented. This would also allow you to group effects by "rarities" or "power levels", so that you can get a very powerful unit (something that heals nearby allies, for example), at the cost of a more powerful tower, such as an AoE unit that disincentivizes the "always bunch units up" strategy. It would also allow for more robust interconnection of your current mechanics, so there's more ways of interacting with different unit types.
Also, small issue: since you're often spam clicking to keep your units of the same type spawning together, but the buttons disappear and move if there's no more of that unit type, I often ended up sending a unit I didn't want. Maybe you could disable the interactable field on the button instead of disabling the object so that this doesn't happen!
I realize most of this issues are probably due to time constraints, but I encourage you to keep working on this project, the idea is very solid and has lots of potential!
Keep up the good work!