A while back I came across a discussion talking about combining the 3 different versions of the Ion Blaster into one weapon. I thought this’d be too much of a change, so instead I proposed that the Original and Flash versions of the weapon be made unlockables. So I decided to redesign them. Both of them ended up having an 11th power level (just like Boron Railgun) for consistency reasons.
The Original Ion Blaster from Chicken Invaders
Power levels 0-7 are kept nearly identical, 8, 9, 10, 11 and 20 are added, all utilizing the double projectile. It keeps some of it’s characteristic features (like 4 not having any projectiles fired directly forward, having up to 7 single projectiles used at once and, at later levels, having the sidemost (is that even a word xd) projectiles fired at a wider angle). In the end it deals exactly the same amount of damage as the regular Ion Blaster, but having an 11th power level gives it another step to level 20. So it technically is more powerful (though it also has significantly more spread).
The yellow Ion Blaster from the flash version of Revenge of the Yolk
The weapon keeps it’s characteristic triple projectile. Another power level is added between the 3rd and 4th one from the flash version (once again, for the sake of consistency), levels 10, 11 and 20 are added. The weapon ends up being slightly more powerful than the other two variants (@20: 1500 damage per volley, compared to 1400 of the other versions).
Obtaining and use: as I said, I think these weapons should be unlockables. Activating one of them replaces the standard red Ion Blaster with the corresponding variant (and, of course, only one can be active at a time). As for unlocking them, well…
I think there should be a small number of unlockables that aren’t purchasable with keys but instead require the player to do something in game. These weapons, for example, could be unlocked for completing a specific mission on a specific difficulty level (maybe a short 10 wave mission resembling that of the original Chicken Invaders?). And since you appear to be adding a lot of new difficulty levels to the game, I’m sure you’ll find ways to make this sort of thing at least semi-challenging.