Nice work on the game :D it was quite nice!
I would set the pacing of the game a little faster, set the default move to WASD and set different noise effects for some coins (like the Purple coin and gold). The power ups can also show what the power ups will be by having some effects to them rather than a blinking Red letter.
Other than that, it's quite good! Just needs some small bits of polish to make this more effective :D