Bloons TD 4 features several tracks with varying levels of difficulty. The easier tracks feature more convenient locations for placing your defenses and tend to be longer. You can also set the difficulty level, reducing the cost of purchases, amount of levels, and increasing your lives.
2 Brand new challenges for you - the lollipop challenge and the feared but super fun MOAB challenge. Get in and play already! BTD4 features improved graphics, loads of new and original tower types and tons of upgrades for each tower type. Heaps of tracks, save games, career mode, sandbox mode and apopalypse mode. Bloons Tower Defense 4 will give you almost unlimited replay value. Also included is optional MochiCoins premium content featuring lots of extra tracks and special booster upgrades like double boomerangs, exploding darts, and double cash!
There are 16 unlockable new weapons and defenses the further you get in the level. Most of these items can be upgraded to deal with new threats and take down enemies more efficiently.