The Best Way to Highlight An Enemy

Hi,

I'm working my way through Burgzergarcade's most excellent "Hack N Slash" tutorials. His game is a 3D game but mine is 2D, but I have been adapting a lot of the scripts and it's working out pretty good. Right now I'm working on targeting. You might say "Why would you need targeting in a 2D BeatEmUp?" Well, it's hard to explain. Anyway -- he changes the material color on his targets which seems to work, but I'm using sprites and looking for something a little different. I've been doing research and there seems to be multiple ways to do this: changing the shader, using a projector, changing the texture, etc.... But I'm not sure how to proceed. It seems as though projectors are more for 3D games and plus I don't really want fancy effects as it's a hand-drawn game. I'm a little unclear about shaders and how they work, though I have been reading -- but I don't know if one will work with the look of my game. I've also considered changing the texture, maybe to a different version of the sprite, or a bigger version, or maybe making it pulse.... I don't know. If you were making a hand-drawn game, which would be a simple but elegant solution I can research that's effective but not loud? With Unity it's like the possibilities are endless, and that's kind of the problem here.

Does anyone have any advice on how I might proceed? My brain can't seem to wrap around the obvious on this one.

Thanks for reading. This is a pretty integral feature of my game.