I liked the game concept! 

I wish the player moved faster and there was less distance between points of interest. Travelling multiple screen-lengths of just straight hallway gets boring. Player's ghost power is cool, but seems repetitive to use, since it feels like I'm using it the same way against every enemy. Maybe there should be a cost to this power, and add another way of dealing with enemies that doesn't have this cost to force some variety.

The graphics jitter strangely when I play in Chrome browser.

I like the concept, it was fun to play!

Neat little game. The music was very good I have to say. It added a lot to the feel of the game. I think feedback to the player if the ghost was doing damage would be nice as I clicked but wasn't always sure I was hitting enemies.

Ghost mode as teleport = awesome. ghost mode leaving your body behind, making you vulnerable = awesome. I agree with other comment that I wish the pace was a bit quicker. Perhaps if your ninja was fast, but your ghost was slow? Or if there was a time limit on ghost mode instead of a distance limit?

I do think this mechanic could be turned into a full game, given more time. Nice work!

Using ghost mode to teleport around was really cool! It'd be a great mechanic to build a more focused or pacifistic stealth experience around. Given a faster pace of gameplay I think you have the makings of something good here. Keep it up!