A tower defense game is all about control. Knowing and guiding what's going on. Using your analytical skills to overcome chaos. Outthinking a superior enemy and defeating it in spite of its superior numbers.
And what's the #1 thing you need in order to analyze? INFORMATION.
Where are the tooltips? I got a new tower, but when I started the next fight, I didn't remember exactly how it worked. I just had to plant it and see what happened. That is the opposite of fun.
It begs me to open the encyclopedia so I can see info on the enemies, but the special attributes are not explained. "Squishy", eh? What is that? I guess it makes them die more quickly, but if you're not going to tell me how to take advantage of their squishiness, why not just give them fewer hit points? Thanks for wasting my time.
After I finished a level, a picture of something and a name came on the screen. What is that- an achievement I unlocked? A skill? Where do I find out about it?
And on and on. There's a difference between challenging and frustrating. This one was the latter. Maybe if I'd played it more, it would have gotten better...but why? I can go play better TD games on Kongregate for free, and most of them are fun and informative right from the first level. I think I only paid like a dollar for this game, but I still want my money back.