Looks like the game can handle 6 colored sprites at a time now! Here are some more changes:

• All of the main enemy sprites and bosses have been redesigned slightly, giving them proper legs! 
• Bosses have more animations for their attacks.
• New FINAL SLASH animation for defeating bosses
• Carrot Rebound now properly renamed and redesigned to Wasabi Rebound.
• No more free Wasabi. Sorry.
• New Power-Up: Frost Cream! Freeze your enemies!
• New Power-Up: Bouncy Donut! Send four wall-bouncing bullets!
• New Upgrades (total: 23), including (but not limited to) a bucket of water, a four-leaf clover, and gag teeth! ...no, I am not making this up.
• Upgrades are now colored
• The Buntender has some dialogue for the upgrades
• Official description of upgrades are more direct and serious
• Other quality-of-life changes
• New bugs I'm sure to find out in the future!