Played up to the last level. This is one of those games that gets better as it progresses.
I overall like the level design. You have a lot of mechanics and they do come together in the last chapter. However, that also makes the game lack focus. The timed character swap mechanic is neat and fits the theme but it is extremely disorienting. I think that is my least favorite part of the game. However, I really like the zombies.
The multi room puzzles are a bit disorienting but they are quite enjoyable too.
The spreading disease wave is realtime. That adds a lot of pressure(which is a good thing) but also makes the undo button less useful. Perhaps it should spread when the player does. That would get rid of the dexterity requirement.
The visual presentation needs some work. This is not about the graphics. I think they are fine. But it was not immediately clear that the little block moving across the player sprite shows how many moves you have before the next teleport. It is also hard to keep track of when the player is making a beeline to the exit. And I originally thought that the blue spreading thing was water. I think that is a mistake a lot of players made.
Overall, I think the game has the potential to go in multiple directions with more work. I hope I was not too harsh. When I play interesting games I turn into Mr. nitpicker.
Great job!