Unclear how to unlock certain weapons

[Pezzo]

For example, I want to buy/unlock the M7 cannon. For some reason the option is not available, and the game gives no indication of why that is. Pressing X for research does nothing, if that's even related to the above problem.

[Pezzo]

Oh, just saw that it's a reward for beating Sector 7 - A1. The armory should tell you this.

[Queco Jones21]

Yeah I agree.

Also no clear way to see when you unlock Tier 2 upgrades... Think I had to defeat all 3 available levels or buy a certain amount of upgrades? No clue since it did not state it anything.