This is a decently polished start! I think the thing that sells the feel of the era for me is the slightly meticulous controls that require you to manually pick each of your units to see what they can do before moving on, etc.
A few things would make this pretty perfect in my eyes:
- An action counter above each unit's head, or maybe just make their sprite dim when they're out of actions.
- Show the range of the enemies, either passively or when you cursor over them.
- A toggle button to switch between units instead of clicking on each one manually.
- Better indication of where the doors/buttons are. I got stuck in the second level because I didn't realize that one tile to the right would turn on the light and let me progress.
- End turn automatically when all friendly units are out of actions.
Like I said, this is really good, otherwise I don't think I would be able to distill down my suggestions so briefly lol.