I came back to the game and beat all campaigns except for "NG Legends". I suspect that beating the "Hope for the Best" bot is very luck-based, so I gave up on the Killer of Legends medal as trying over and over would take too much time.
After all of the hard work spent trying to beat every single bot, I have gained an appreciation for the strategy involved in this game. In fact, I would now consider Cathode Raybots to be primarily a puzzle game, even it seems like an action game at first glance. Most supposedly hard stages have a weak spot, where standing and firing continuously, when combined with a few jumps to dodge projectiles, allows you to beat the stage easily. For example, standing at the rightmost or leftmost (the stage is symmetric, so you can choose either one) reachable point in Sabortion and continuously firing leads to a narrow win. Heck lvl1 appears to be impossible, but after some trial and error, you may find that hitting the bot with a charged shot every 4-5 seconds is the solution. To those who may be reading this: the main message is to try to find a weakness in each stage so that you can win it reliably. Don't be that person who prances around like a monkey firing shots randomly; you'll just end up failing to beat most campaigns.
I have nothing to say about Raybot mode, as I didn't construct any patterns or stages.
Also, the bug where your character freezes and then utters a victory expression such as "Welcome to Earth" or "Smoke em if you got em" at the beginning of a battle persists. Luckily, reloading gets me back to the main menu pretty quickly, so it's not so bad.