Minecraft Zombie
3 games
Description
Blocks and zombies go together for a practical reason: a blocky world is easy to build defences in, and zombies give you something to build them against.
Mine Fight! Cut Mob Army! is the direct one, putting you against waves without much preamble. Trap Craft is the more interesting take - you're setting traps and letting them do the work rather than fighting anything yourself, which turns it into a planning game. Farm: Nubik Vs Zombies borrows the lane-defence format and puts it in a blocky world. None of them need the original game to make sense, and you'll be building something defensible within a minute.
There are 3 free games under this tag, all playable in the browser with nothing to install, and none of them need the original game to make sense.
The building side is Building Games, and Action games covers the ones where you're doing the fighting.