Gotta do something about the end game. As others have commented, need to be able to choose how many gems we're using. Other than that, need to mix up progression some by giving players a reason to keep pushing to the next monster. Currently, once you purchase the best weapon, you "level up" at the same rate on the fist enemy as you do on the highest enemy you can one shot.
Give the money value beyond weapons. Or, allow us to "upgrade" the final weapon for a fee (or hell, every weapon).
Fun game. May I suggest finding a way to synergize the other boards better? As it is, the only board that does anything to the others is the farming one. Paddle and shooter are left pretty quickly, because jumper and mower are simply better. If paddle and shooter somehow buffed the others, it might make them more attractive.
Easy path: Upgrade speed and basic gun, rockets can be useful, too. Once at level 9, get acid and upgrade until the level 9 becomes a cake walk, then focus on upgrading your laser and shoot for level 13. When it comes to the laser, focus on the damage, and secondary. You want to make 13 easy to farm, and use the points to upgrade all of your ship's basic abilities. Then max out your pulse weapon (does more damage than maxed laser, I know right?). Final boss is a pain, but doable. Good luck trying to pull it off without taking a hit.
I don't understand why anyone would want to reduce the recoil. If anything, I think the recoil should ramp up significantly after the first few shots to encourage controlled bursts over spraying.
As for the aiming, it feels a bit strange to have a click-on click-off aiming system. With a hold to aim system, the slower turning would feel much more natural. I also think players should move slower while aiming. Of course, I'd also like to see iron sight aiming, and slower movement altogether.
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 "Reactance"){kind=icon}
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