I made “7 Hours ‘Til Sunrise” during a heyday of a lot of Left 4 Dead. It is a simple mouse controlled defense game. The objective is to prevent the zombies from reaching you (the farmer) by using an arsenal of weapons, which can be upgrade between enemy waves.
Each weapon has a bit of “kick” to it (conical shaped margin of error), which slightly improves as you upgrade it, except for the shotgun. After the fact, I suspect the shotgun turned out to be a bit overpowered, but I left it in because as someone put it “Just like in every zombie movie, the shotgun is the best weapon”.
This game was done in Flash.