Had a little play thru all the games, heres some feedbacks for each one.
Gingerdude: player moves too slow compared to enemies and is a bit sloppy which makes hard to aim
Jungles of Borneo: player moves even slower than the first one, also its possible to eat all the birds by standing in place and shooting, since they spawn in the same position. Orange screen creeped me out and w/e it was it dropped too fast for me to react. Maybe im just slow
Neon Aliens Shooter: polished and well made, give these guys an A.
Space Whirl: i didn't quite what was happening, but i think it relates to flocks of birds and when i shoot one the others fly away? aim too sloppy too.
Space survival: this one is quite nice too, i just think it's a bit unfair that im able to destroy what could save my life (the yellow thing that clears the screen)
For all of them:
In most cases, for shooters which is the subject of these games, you need to have tight controls to be able to aim properly, except for different mechanics like say, Missile Defense-like games which the bullet was slow and exploded mid air.
I also agree with Rory in the sense they are very basic, try to have students plan a short game with a few mechanics (platforming, then action-platforming or puzzle-platforming for example) and work towards completing it. I'm basing this on my architecture course, where we get like what a specific type of building needs (a school or hospital), and work the entire semester on it. I think it's a pretty nice way to learn not about only conception or final product, but the entire process of making it.