Actually, this isn't a review, but kind of like a helper review. Just, read on, ok?

User Rating: 9.5 | Heavy Weapon Deluxe PC
In this review I'll just give out suggestions in what weapon upgrades you should use before each mission, such as follows:

Before M1: Normal gun only, of course.
Before M2: Normal gun plus one defensive orb.
Before M3: Normal gun, one defensive orb, plus one laser.
Before M4: Normal gun, one orb, one laser, plus one heat - seeking missile.
Before M5: Normal gun, one orb, one laser, one tracking missile, plus one
thunderstrike.
Before M6: Normal gun, one orb, two lasers, one tracking missile, plus one
thunderstrike.
Before M7: Normal gun, one orb, two lasers, one tracking missile, one flak cannon, plus one thunderstrike.

End of part 1

I wrote those above to help you to choose the right weapons to upgrade before
each mission, and because those are the configurations I used to plow through missions 1 - 7 ---- without dying. But, if you are more satisfied with your own configurations, I under stand you, because this guide is only for the ones who needs a hand on how to upgrade their weapons carefully, and effectively.