Challenging, but not ridiculously hard. An interesting combination of forcing you to change tactics, but still letting you keep your own style whilst playing. Good work ^_^
Quite nice idea, can't really complain about the controls and the style of gameplay. All I can complain about however is the lack of length, you give us what, three levels? And make them feel like an introduction.. At least 2 more levels and a bit more to the story and maybe then it'll be worth 5 stars, but as of the minute 4 is what you're getting.
Don't follow Jonathan Boydoo8's advice on level 8, his way may be safest but it's actually relatively easy to complete that level alot faster, just build up your defenses and toxins at a rate to keep up with the viruses.
@TheIncredibleMrB: Yeah I remember it, and you know what? They weren't lying. This is nothing like any of the previous protector games and is an entirely new game of it's own right.
It's not that hard a game really... Just completed it first run through... If lags your problem I don't think it's the game. Maybe your browser or RAM... This has alot less lag in it than Bloons TD4...