Can u buy at least weapons? Without them it feels impossible.

Yes, weapons have to be allowed. What do you think about crash and armor packages?

I think its just denies the purpose of the category. I'm gonna try beat it without.

You can probably get the campaign done with minigun only if we're going for extra challenge with this category.

So it's possible to do with only weapon upgrades, however u can't beat final mission with only minigun.

You can complete the whole game without absolutely any upgrades and even weapons. Only the last mission requires you having at least rockets