A great alternative to all the tower defense clones
This game surprised me with nice clean visuals and generated levels that mean you aren't going to be repeating the same battles verbatim, even on a second bash at the campaign.
The cash in the game builds up from level to level, so if you finish Level 7 with a ton of left over cash, Level 8 is going to be a much softer ride for you. But if you blow all your cash... Its an interesting mechanic but the player is never really given much guidance on when they are going to need a wad of cash to fight a tough battle, or whether they are going to be able to breeze by with couple of cents. Some players will tend to hoard all the cash they can, then find that the lack of teching up earlier on has royally buggered them in the later battles.