It's a mix of turn-based battles with some real-time base building. The base building aspect is a little like XCOM 2 with a side-on view as you dig out rooms. The whole game feels like it was inspired by XCOM 1 & 2, as you send over units to different regions to perform missions. You even speed up time at will when outside of missions, so it's all very familiar.
The game was funded thanks to Kickstarter, where the developers nabbed $306,537 from helpful people wanting to see it become a reality. It's also nice that another Kickstarter team actually managed day-1 Linux support.
The team behind Overload actually has some of the originally Descent team and the co-founder of the studio even worked on Freespace 1 & 2, which are my two all time favourite space shooters. I'm really not surprised the game has already turned out so well!