For question 1, not having the germs fight back does make the game easy, because at the moment it is basically just a game of a circle collecting random triangles around the screen, with no real conflict.
For question 2, I liked the fact that you could see everything on the screen, as it would make it easier for the player to avoid potential enemies, but you should add some conflict to the game in order to make it more engaging for the player.
For question 1, the two blocks at the bottom of the screen are an okay indicator of going to the next level, but you might want to make those blocks a different color so that the player can tell that that is where you have to go to get to the next level.
For question 2, the game layout is kind of confusing, as it is just a bunch of shapes thrown together, with no real indication of what to do (I am not able to interact with any of the shapes, since I don't know what button to press for what), and it only takes up a small fraction of the screen space. Yes, continuous collecting/strategic trading would be a fun concept for a game, as it would be engaging to the player.
For the first question, the game evoked a sense of wonder, because of the fact that we are seeing through the perspective of a 12-year-old. It did not capture a feeling of nostalgia, because it seemed like it was more a reflection of one singular person's memory (i.e. the whole mention of Manasquan Reservoir, instead of a generic place name).
For the second question, the limited mechanics were okay (but not great), in the fact that the player was sort of limited to pre-determined guide lines on the screen.
