In general, I shy away from Flash-based games. I am not sure whether it is because of the low quality of most Flash games (i.e. stick figures) or because I feel guilty about wasting time or simply because most of them are not really that much fun. There are only so many times you can play Desktop Tower Defense before you start wondering why exactly it is important that those little blobs with faces do not make it past your towers.
The zombie-oriented game "The Last Stand" is different. As the creator of a fortified house in the midst of a zombie outbreak, you are forced to shoot zombies during the night and choose between repairing damage and searching for weapons and other survivors during the day. There are several different guns (and one chainsaw), which accommodate a variety of tactical styles. Unlike the generic "Oh noes, your enemies have passed off the edge of the screen" defeats present in the other Flash games I mentioned, if the zombies manage to destroy your barricade, they slowly advance upon your person, eventually clawing you to pieces in bloody full-color graphics.
My only issue with the game is that it is linear and has limited replayability. Last night, after coming home from a party (actually, it was this morning, but I digress), I succeeded in beating the game without ever repairing my barricade. When you have to self-limit your gameplay, it is probably time to move on.
I am tempted to go to the midnight showing of 28 Weeks Later at Harvard Square, but I am forcing myself to stay home and do some web design stuff.