Gameplay was fine, nothing too exciting though. I had no idea what the scanner stat did because I couldn't fit the entire game on my screen, which was mildly annoying. While playing it again for this review I still can't tell what the scanner does. Regardless, the game was very easy with the slave 1; I didn't come close to dying at any point and the final boss was laughable. It's probably more difficult on mobile though since they can't use mice.
About the powerups: I couldn't really distinguish between the bomb and the shield before I picked them up, not a big deal though. They spawn too quickly! It's easy to stay topped off since they drop to the bottom of the screen and you can pick them up without any risk. If you wanted to make the game harder, decrease their spawn time, have them float around the top half of the screen so you have to take a risk to pick them up, and have only 1 be on the screen at any point. Currently it's way too easy to stay topped off at full hp.
3.5 stars since the game is solid, good controls and music.