I found the best team to be 2 robots 2 fairies. The reason being farming the robots ability, vending. Don't kill the slimes and let them follow you, whenever you can use the ability to drop the candy. If aliens are still on the screen the level won't end, allowing you to run around the screen and drop candy while also healing any damage you take with the fairies healing. Try to avoid killing the slimes as long as possible. Only put money into the special stat, and if you have any left over put some in speed. Do this for the first 4 or four stages and you can buy most of the upgrades. I advocate using this technique and also suggest that it is fixed, maybe forcing slimes off screen after a brief time.
like all zombie games the more guns the better, i'm not sure if it's a glitch but if you hit reload while reloading you restart the reload. If so it would be nice but not a big deal to have it fixed.
That text only plays the first time though, and is meant as a means to teach you how to play. You can turn it off if you like in the main menu of the game.
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maybe you found a self-hating customer