Commands:
gamepad or keyboard (A,S, cursor keys, space to pause)
Esc to exit.
To skip the opening (the story that launches when starting the game), just hit the Fire button to advance the text. To skip the cutscenes, press and hold the fire button (a notification will appear on the screen). The intro that plays if "NEW" game is selected cannot be skipped.
Of course many things are not finished, but it should give an idea of where is it heading. To get the proper idea of how is it supposed to work, select "NEW" on the main selection screen (you can also select "CONTINUE" - I left all the levels unlocked for easier testing). btw even if you select "NEW" the levels will remain unlocked (again, for easier testing).
Edit: Everything is quite different from the last time I showed it - some changes are major (menus, pausing! it works!) some minor (cutscene elements are tweaked, deleted or added, new music, explosions now have proper color, various effects etc etc) - too numerous to list, best to see for yourself
