Well there is a lot of good stuff here, and a lot I really like, particularly that you managed to really capture the feeling of an old school platformer ala turrican or metroid, the music, the graphics, I felt like I could've been playing this on my Snes.
The jumping system took a while to get used to, sinse sometimes it seemed you would walk along slowly, and then rocket into the sky for no reason, I also wish the game had some look up and down buttons sinse with you constantly in the near center bottom of the view jumping between platforms on the same horizontal level was rather harder than it should've been sinse you couldn't see your destination (the float ability made up for this partly but only partly).
I absolutely loved the speaking tutorial panels. As I am visually impared and can't read text this is the first time I ever got a tutorial which worked, which was great! indeed if you want to voice more stuff in the game that would be awsome.
It might also be nice to distinguish forground and background elements a bit, sinse while I really liked the contrast on most of the game, and the fact that there were a lot of large and very easily visible characters,things, occasionally background and forground elements could get confused, particularly with those floating clouds at the top of the first level.
Do you also have plans to add extra enemy explosions, hit and damage sounds? sinse as it stands there were points when i wasn't certain whether I was being damaged or not, for example does jumping on enemies hurt you or can you jump ontop of enemies to kill them mario style.
The only thing I couldn't work out was the power up and weapons system, sinse it seemed sometimes I picked stuff up and got a bigger gun sometimes not. It also seemed all I could do was walk left and right, jump, shoot and duck which was a little disappointing sinse it would have been nice to have more abilities to play with.
I'm not sure if I missed something somewhere in terms of buying things with pointts as you said, or if I missed some abilitties somewhere (I tried all the obvious keyboard keys but no luck).
Lastly, what is the deal with energy, powerups and saving? I finished the tutorial, explored much (possibly all), the first stage and got to stage two, picking up one ups and such along the way.
I begin the second stage, fall down a hole then am suddenly at a sequence where I'm floating down avoiding large red enemies, about three hits in and I'm dead and right back to the start, which was irritating.