I had to install several libs to get it to work, for users reading this use ldd to spare you some time:
ldd bin/Plantower | grep 'not found' sudo apt install libsdl2-2.0-0 libsdl2-image-2.0-0 libsdl2-ttf-2.0-0 libsdl2-mixer-2.0-0 libtinyxml2-6 libb64-0d bin/Plantower
I only got one segfault, and I was about done playing.
This was a challenging game to rate... you don't get two categories with the same rating!
Theme interpretation
1 star - I don't see any link to the theme, maybe it's not implemented.
Gameplay
2 stars, I looked at the source code quickly to see if there were any controls that I missed but apparently all you can currently do is move and attack, it's quite fun to try multiple kills but it feels pointless pretty quickly.
Graphics
I'll give it 3 stars, again quite fun to look at but I'm still not sure if it's more 3D or 2D.
Audio
4 stars, the music is really nice and somehow feels fitting even if there's not much to fit to
Innovation
I'll go with 5/5 with regards to what could have been, because your description of "action adventure tower defense crossover" feels ambitious but really fun. Hope you someday get back to it and show me what you meant by that!