Asia, the first unlockable character for 5000 coins, is hideously overpowered. Base collect range of 15 or so (other characters are like 2...) and her default weapon with all red upgrades is INSANE. It will eventually grow to hit the entire screen at once, and if you take even just a single 0.1% lifedrain perk it can heal for hundreds per slap (I usually have 120 or so HP...).
https://1fichier.com/?undd3p2bsjg1b5x4bqwc&af=2701919
https://www.youtube.com/watch?v=DrcUoJjkAmk