I really - really - loved the core mechanic of this entry! The fact that you can become the parasite for your adversary and gain their power fits perfectly to the theme, and furthermore it blends very well with the "rock-paper-scissor" concept. When playing this, I was amazed by how nicely you've been able to mix the theme and the wildcards in a solid and cohesive game: I think your submission is a great example of game design, congrats :)
The only critique that I can make on the gameplay, is that the game could end when one player injects their target. In this case, in fact, the "rock-paper-scissor" balance is broken, and the injected player would have a hard time in recovering...
The graphics elements were well made, but I liked especially the "flux" animation of injecting an adversary. Unfortunately, I wasn't able to play it in full screen, and my grid was cropped on the right :(
I'll look forward for a fixed version of the game. Again, great entry and congratulations for your first GWJ! :D