For those unaware, the Bloons TD series consists of tower defense games where you place monkeys along a track to pop balloons. It's called TD and not Tower Defense because a scumbag company decided to trademark the name of an entire genre, but that's beside the point.
Since the series's debut as a flash game over a decade ago, the games have evolved to contain a wealth of strategic complexity. Aside from the towers having different attack rates and ranges, there are different types of damage (e.g. popping, fire, explosion) that make each tower unique. Additionally, the balloons occasionally have resistances to certain types of damage. This forces you to be creative with your tower placement, and opens each game up to an incredible depth and variation. This helps keep the game fresh and exciting, as you try out different strategies.
...Or at least, it would do that if it weren't for the arbitrary roadblocks the game puts in place. Presumably in order to ease new players into the mechanics, you're forced to unlock everything through gameplay. This doesn't just include new towers, tracks, and game modes -- you're forced to unlock every single upgrade for every single tower. You unlock these by using the towers to earn them XP.
In theory this wouldn't be so bad. You could argue that it makes you learn the strengths and weaknesses of the towers before you can upgrade them. But why is that learning forced on me by the game? Why can't I learn at my own pace? I care so much because the game's pace is hellishly slow. You will certainly have to spend time grinding in order to unlock everything.
If that sounds ridiculous, it's because it is. I should not have to grind in my mobile tower defense game. I've been playing for two days now, and I'm still incredibly far from being able to play without restrictions. I'm mentally preparing myself for the long haul on this, but I can easily see this alienating new players, or those who just want to experience all the game has to offer.
It really is ridiculous when my own attempts to win the rounds are foiled because the game won't let me have the upgrade I need.
The other major problem I have with the game are its in-app purchases. Ninja Kiwi, the developer, seems to adhere to the despicable model of charging $5 up-front and also charging for things in-game. The game tempts me every time I look at the menu of which upgrades I've unlocked. "Don't you want to use this tower now, instead of many hours from now? Why not pay $5 to unlock all of its upgrades instantly?"
There are in-app purchases for different amounts of Monkey Money (which let you continue to play a failed game) that range from $2 to $55. Double Cash mode, which in previous games was unlocked through playing, now costs $19.
There are good points to this game. The graphics are 3D, which is quite different than the older games, and they look good. They're not an outstanding visual pleasure, but they also aren't irritating or ugly. The word I'd use is serviceable. I preferred the cartoony graphics of Bloons TD 5, but I can see myself getting used to these.
The music is also adequate. Different tracks may have different music, but the repetition may have you cringing as you grind, grind, grind away for hours at unlocking everything. At 20 tracks, there is certainly enough variety to help alleviate some of the drag, but you also have to remember that the more difficult tracks are likely impossible to beat if you still don't have access to every tower's upgrades.
So there you have it. I give Bloons TD 6 three rubbery balloon-husks out of five while shedding a single disappointed tear, because all the fun is locked away behind hours of grinding.
Or you could pay real money to skip all that and actually have fun. Ninja Kiwi, you've broken my heart.