Hey ho!
This is a good base but needs more development.
first of all The graphics lack detail (specially talking about the buttons which look kind of cheap - no offense) (1/5)
The statement "a tunnel full of explosive mines" did not fit in my opinion, though the mines were more sporadic and most easy to avoid. I did not have the feeling of it becoming harder either. I won't include the Controls into my rating because I do know there is a whole gaming-genre evolving around games using the spyce key to beat the entire game only. (2/5)
There is no Sound in this Game (Well I did not hear a thing), so: (0/5)
Overall:
1/5 + 2/5 + 0/5 = 3/5
/3
= 1/5
There is definitely room for improvement, but as I said, this game is a good base to do so. :)