Cool game. Not anything groundbreaking, but a very solid 3.5 stars.
1 star for graphics that were good enough that I could tell what everything was. Animation & other presentation had no lack of frames or other issues.
1 star for being nearly bug-free and having a logical and easily learned interface. The only glitches I could find came up near the end and were as follows: If I tried to cast a spell that I was out of while holding my boomerang, I could subsequently throw two [sets of] boomerang[s] at a time instead of one until I selected something different. If I had a depleted item selected when my stocks regenerated, I had to re-select that item in order to use it even though it was no longer empty. Finally, I'm not sure what the circumstances were, but after one of my wall traps was destroyed on the last level and my traps regenerated, I was unable to place any trap in the spot that was occupied by said wall.
1.5 stars for keeping me interested almost all the way through. The difficulty curve was parabolic; the monsters became more durable slightly faster than I could upgrade at the beginning, resulting in increasing difficulty (this is desirable). However, many upgrades had synergism that made my ability to do damage and halt the enemy advance far outpace their increases in health and numbers by mid-game. At some point well before I obtained the regen upgrade, I would have difficulty expending my entire stock of weapons, spells, and traps over a given level. The synergism I'm talking about is between the weapon/spell levels, effect plus, damage plus, and bounce. Particularly, any level 3 weapon with effect plus 3 and bounce was pretty unstoppable. Level 3 spells combined with spell plus 3 were essentially all screen-clearers. Granted, I didn't have access to said combinations until the last level, but the last level should have been the hardest, and I was bored.
One slight gripe about the upgrades interface. It looks a lot simpler than it is. At first glance, you have a set of columns, but the fact that the levels of each upgrade were split amongst the columns makes it more like a rather complicated tree. At times, the phrase "Locked" was less than helpful because it wasn't immediately clear whether I was missing some prerequisite or I just didn't have enough coins. That seems like a really easy thing to fix.