I have something playable now in terms of one level. It would have been done sooner, if it weren't for a really easy to miss bug that plagued me for two hours yesterday. Glad I fixed it, because it was game-breaking. I currently have a win condition set up. All it's missing is a title screen and a Game Over screen. I would show some gameplay footage if I had the means to do screen capture. Didn't install the software for that ahead of time. I'll have it next time, though. For now, have a screenshot:

The gray blob is the player, a white blood cell. The red and blue things are germs inside the body. Your goal is to use randomly-spawned colored pills to power up and kill germs of the same color by eating them. You take damage if you're the wrong color or if you're gray. Pills have a time limit on how long they stay active. Today, I'm going to get a title and Game Over screen working, as well as add some additional visual effects, sound, and maybe a biological hazard that you can't kill, but need to avoid if it shows up. Feeling good about this so far!