Tower Defense: New enemy and spells!

So I made two big  additions since last time: added a new type of enemy and added spells.

I wanted to add a new enemy for a couple reasons... Previously the only way enemies were different or harder was their health was higher, and it could only go up so high since it's based on color values (the max was (255,255,255) which is white). If you put down a couple of white towers on the level, you were pretty much set and could kill everything no problem. So I wanted to add an enemy that would be a bit harder to kill, and act sort of like a boss. One thought was of splitting enemies... when you kill them, they split into smaller enemies. So right now I have splitting enemies that can split up to 2 times, and into however many enemies I want (it's just 2 right now). It's a lot more difficult to handle these things, since if you do kill them you now have even more enemies to kill.

I'm also trying to figure out a way to have high health enemies that aren't white, because right now there's no point in NOT getting a white tower. I want to have a red enemy that has as much health as a white enemy... this would incentivize having a high level red or magenta tower. As of right now my only ideas for this are adding enemies that have more than 255 as their color value, which would sort of act like a shield. So that's something to think about.

The next thing I added was spells. In a lot of tower defense games, players can use spells to interact/affect enemies without using towers and I wanted to add this to my game. My original idea was to have a paint brush effect that fades away and if enemies move over the paint, something happens. Unfortunately I couldn't really figure out how to produce a paintbrush effect and I think figuring out collision would be difficult. I ended up changing it slightly to be throwing paint onto the path. So right now there's three types of paints (three spells). There is red paint, which does damage to enemies that move over it, green paint that gives you money when enemies walk over it, and blue paint that slows enemies moving over it. I want to put these on a shared cooldown to make deciding which spell to use more important. So for instance if you want to thin out enemy numbers, you can use red paint or if you need more money to get the third upgrade for a tower you can use green paint. Maybe enemies are approaching a point in the path with lots of towers next to it so you can use blue paint so they take a lot of damage from the towers. I think it will make gameplay more interesting and more interactive.