This is actually a nice game to play! I like TF2 as well and I happen to have the engineer as favorite class (Engineer, ftw!). I must admit: this is actually entertaining unlike many other spoofs, I say you did a job well done!
Oh, since you made this game, you can take this kinda, your own way. Would you like to make your own engineer weapons? go ahead! Want to make your own sentries and contraptions? Go ahead, you got your own game on which you can build! I'm looking forward to an eventual sequal.