You wont get far in the game without the upgrades… They are worth the cost, the game is a blast!

The game is very fun and requires a bit of strategy.
A very bright and colorful entertaining challenge. I would recommend it.
Having said that I would like to share my thought that, calling a game free that cant be beaten without purchasing upgrades should be stated by the maker. Their description implies the game doenst need the add ons to be finished. Im just frustrated with "advertising" that leads one to believe one thing when quite another is true.
Better to just come out and call it a trial than to tell people it can be played for free and that "add ons only enhance gameplay". Tell us that we wont finish the game without dropping 4 bucks. The 4 dollars was worth it for me because the game really is cool.
The following may come off as arrogant to some, its not my intention to offend. Having said that the following sheds some light on my thoughts.
….….Integrity is a concept of consistency of actions, values, methods, measures, principles, expectations, and outcomes. In ethics, integrity is regarded as the honesty and truthfulness or accuracy of ones actions. Integrity can be regarded as the opposite of hypocrisy,[1] in that integrity regards internal consistency as a virtue, and suggests that parties holding apparently conflicting values should account for the discrepancy or alter their beliefs.

19Lee63 about Radiant Defense