In order for ME to get the 5M challenge, I had it set to "In & Out" and "Fixed". If I didn't get a rainbow shape within the first 20 or 30 seconds, just restarted. Should have no less than 40x after the rainbow, too.
FEATURE:
If you've already maxed out the skills you can acquire, the Skill Store should not pop up between levels. The user should have to click to go into the store (though for what reason, who knows?)
Would like to make this 5/5, BUT...
When you go 3 waves without a powerup, something's wrong. Should have at least one powerup per wave when weapon is not fully upgraded. Otherwise, this game is about luck and not skill
If you're having trouble getting out of the Mech Shop it's because you haven't added any weapons to your Mech. After the first mission, you determine what weapons go with you, so they are automatically stripped off after the mission ends.
I enjoyed this a great deal. I thought the rune and trinket system was interesting, though ONE trinket in particular seems to do a great deal for the player. Would love to have had more levels to play through.