Thanks a lot! ^_^
I like your suggestions and I think if i was to make a similar project in the future, I would add those kinds of feature. I really like the shield idea, its not something I had considered.. I think I was initially hoping to add some kind of speed buff as a stretch goal but I never got around to it..
I have a few ideas for how I'd make killing the spawners more worthwhile to kill so i'll try to implement those in my next project. Thanks for the constructive criticism and I hope you enjoyed playing! :)