Unforgiving? Yes; Hard? No
I wouldn't describe this game as brutally hard. As far as reflex games go, this is rather easy. Any "difficulty" comes from three places:
1) Controls: The description of the controls is ambiguous. To some it seems to imply that space does the jumping, blocking, dodging, sprinting, and javelin throwing. This could be improved by separately describing the controls (W - jump; A - Block; etc.) or by adding "respectively" inside the parentheses.
2) Length: The levels just get longer and longer, without any indication of how long until your character yells about needing to sprint for a big jump. Something along the lines of a progress meter or a "feet left to go" or whatever could be nice. Sure, this does not help you get through the level, but it's a nice touch.
3) A single mistake means you need to restart. This does not make a game "hard", just means that you must be perfect. Requiring perfection is either just annoying or realistic, but still not hard. Other reflex games make themselves harder by gradually increasing the speed, making the timings trickier, etc.
Comment:
I found the sprint button rather useless. I either used it only at the absolute end of a level for that single jump, or I was holding it down for the entire level and just playing a faster reflex game. Maybe I was using it wrongly, but I think it would have served better as a toggle button.
