Still Pretty Easy
For all the new towers now available, the Bomb tower remains overpowered. It's largely the only tower needed, with possible minor exceptions for ice against bosses and pistol towers early on to maximize total money. Once there's a level 5 bomb tower in play, the game becomes far too easy. Even a weaker player could probably win with ease by sacrificing a small number of lives at a few key points to raise earning potential.
It's still somewhat fun, but really adds very little innovation over your previous games.