Really nice game, looks quite cool. I was unsure of my ability to attack as nothing on screen indicated that I was carrying a weapon, also I found that when attacking enemies they give no indication of taking damage (unless they die from one hit), this lead me to believe that the first red guy I met was an NPC, but that killed me....
I really liked the climbing mechanic that was awesome. I think you should look into working with shadows and other rendering effects to add more visual appeal to the game, the graphics are good, but lighting always adds to an experience.
Good game in total, with a bit of work, this could be really great. Think about how you inform the player of gameplay mechanics either through the environment or through visual indicators :)