Thanks for the feedback, and for playing :)
The slow mech movement was intentional (tough, now that I think about it, I could speed it up a tad), I sort of didn't want the player to be able to defend the whole planet with a single mech, thus forcing them to buy multiple and have them spread around. I don't think the game did a great job at explaining that, so I apologize.
That's a good shout, with the action buttons for the mechs being different! I'll probably change them both to left click for consistency.
And, yeah, an interactive tutorial would've been the dream, but I didn't want to spend too much dev time on it. I may rework the current one to have fewer images, as you suggested...
Also, them theme was more specifically about leaving behind the people from the planets you evacuate. So the idea would be that you had to weigh the pros and cons of staying a bit longer to save those last few people, or evacuating to protect those already saved. (Again, not crystal clear, I'll add a line to the description explaining it better :))