I loved the graphics. Really detailed despite the limitations with the colors
Like others, it took me a while to understand what to do. I had to read the game description twice and I figured it out with one of the screenshot GIF you have. My issue was mainly the "Synthesize" part. I couldn't understand how to move in that screen and what it's supposed to be doing to help me figure out the puzzle.
With more clarity (like maybe a tutorial at the start) I think it has potential.
For the synthetize part, I'd probably go with a RPG-menu approach maybe ?
1) select the action you want to do
2) if you select to put it on the + part, the cursor moves to the top to select the DNA
3) once you select the DNA, the cursor moves back to the "+", you place it there and it goes back to the action menu where you can press "Synthesize"
I don't know if you see what I mean, it's tough to explain in a comment section!
Overall, the concept is good. Reminds me of "A boy and his blob" on the NES, to solve puzzle using a creatures you carry. I could see it expanded to something bigger!
Good job on your submission!