This is quite a fun spin on tower defence, or forting up! I especially like the graphics for it, don't know why but they seem really toy like, which makes them endearing.
The controls are surprisingly good for the size of the sprites although it gets a bit hard to cycle through them when there's like 30 skeletons on the field. Perhaps putting them to 1-2-3 instead could be an alternative, so the player can always press one for sword in a panic?
Really enjoyed it!