So, your game does have potential. I'm a huge fan of turn-based tactical games. XCom, Gears: Tactics, Dungeons of Naheulbek, Road to Eden, Wasteland 2 & 3... are all some of my favorite games. Here's my feedback, though...
1. Art/Graphics: Characters look fine, but it would be nice if soldiers and enemies had a bit more variety. This is likely a very early build, but maybe give some soldiers different colors, hats, hair, etc. Everyone looks the same. BUT... level design, building layout, and the outside looks well put together!
2. Controls/UI: Your game is lacking in this department. When you move the camera around with WASD... it gets stuck... or lags. Plus, there's no key to swap between soldiers quickly, and I noticed I had to click on the enemies multiple times before my soldier would even fire at them. So, it felt very unresponsive.
3. Sound/Music: Sound effects need some work. Not a fan of the bouncy sounds when you move characters. Maybe have footsteps here instead. Also... no music. It's very quiet. Also... the audio is very loud. When I moved my first soldier, I had to turn my headphones down quite a bit.
4. Overall Fun: Again... some good potential here. You just have a lot of work ahead of you, but you can make this game great. Right now... the buggy controls, no tutorial, small UI, and the fact that enemy turns play out so quickly... it just felt rushed and unfinished.
SUGGESTIONS:
1. Slow enemy turns down. It happens so fast. It was over, and I didn't even realize a soldier died until I moved the camera around on my turn.
2. Enemies have way too much health. I had one enemy surrounded by 4 of my soldiers... they all shot him a couple of rounds... still not dead. Not sure if this is a bug... or if the enemies are hulked-out super soldiers.
3. More variety in enemy and soldier appearances.
4. Music. Something intense and upbeat for combat.
5. Rework the sound effects. The dings and dongs aren't very fitting IMO. Unless you're going for the retro sounds of a classic Atari or NES game...
6. Gun fire SE's footsteps, maybe some environmental ambient sounds... the world around you needs to feel more alive.
I'm sure this is still really early in development, and you plan to fix most of this, but I hope the feedback you're receiving from everyone is helpful! I gave you a follow and will keep an eye on this one! :-)