Sounds Way Too Ambitious For Your Own Good. You Should Only Make The Game Have Singleplayer And Maps Up To BTD5 On Launch And Implement The Rest Of The Features In Major Updates. I Would Know As I'm 90% Certain I Had Killed A Game Project (Which Was Actually Made By Someone Else) Because I Planned Out Too Much Ambition, And Now That I've Learned, I Don't Want Newer Creators To Repeat What I Did.