Great core concept that should be explored further.

Execution is solid but in its current state the game leaves a lot to be desired. Could be better balanced and I'd really like to see enemies approaching from the distance instead of just suddenly popping at the pillars, so I could plan my moves in advance.

When I play it, it's triggering my imagination to think about all sorts of additional abilities and upgrades that could be added.  

Nice game.

Was it only me, or is quick heal way more efficient than the big heals?

Really interesting strategy based game concept. I liked the idea of upgrading a skill or resurrecting a pillar after each year. Maybe add some variation to the pillars. For example you may change their colors accordingly (e.g. green for hope, red for health, ...) or add a symbol on top of each pillar. Is there a deeper reason for your choice of keys (and I'm too dumb to get it)?