"On March 9th, 2014, the last surviving citizens of myspace were killed and it's final city block conquered by the undead who now rule over the entire Earth."
R.I.P. Tom.
This game would be significantly easier and better if when you hit the keys actually lined up with the noise it's mimicking in the song instead of the sound coming a second later. It makes this game really hard and annoying for anyone with rhythm.
To get the hard badge, just get a fair amount of stamina and a weapon that gives you shield. Just run through enemies to the exit on each floor using shield to stay alive. I don't know why it took the impatience of trying a cursed golem for me to figure it out....
I couldn't seem to kill the aliens for some reason, so I went to look in the comments for help, but when I looked back only 1 ship was left. Hurray for auto-pilot?
For Sparta, get a grenade launcher and fully upgrade the damage and reload, upgrade the ammo some too, but it doesn't have to be full. Have 3 missile turrets as your towers, upgrade the firing rate the most you can before you run out of money, or some damage too. Buy gunman with what you have left once you can't afford any more upgrades. You won't need any wall or repairmen, you don't even really need the gunman. It won't take any time at all and it's nearly effortless.