This was a fun take on a shooter, almost like a roguelike, I enjoyed it quite a bit! There were some performance issues with slowdowns for me which made it a bit harder to play, and it was unclear if you could heal and where the shops were at times, but it was quite good!

The lag is definitely a problem. It feels like a 1 frame per sec when there's too much explosion. 

Good idea to show the distance travelled. It adds to the exploration factor. Unfortunately I had some lag in the browser. I think the explosion effects might be the cause.