Questions About minecraft free unblocked games

Minecraft black screen?

Okay, so I downloaded a free version of minecraft from here: http://www.youtube.com/watch?v=7PX6cZ8lodM and when I try to open and play it the screen turns black after loading/updating. I've tried to download multiple other free versions of minecraft as well and this has happened with all of them. I DO have the most up-to-date version of Java (I go and download it everytime I try to play minecraft just for hope) and when I check my Firewall minecraft doesn't even show up on the list, so I can't block or unblock it from my Firewall. I have a VERY good gaming computer, and minecraft even worked on my crap bag laptop. So, any other things that could be causing this problem? Please respond, thanks! No silly answers either please. :P
http://answers.yahoo.com/question/?qid=20120711200745AAipE2A

Roughly how many megabytes is each application?

I'm receiving a new iPod on Tuesday, and on my iTunes I downloaded the apps I would sync onto it. I was wondering roughly how much space it would take up. List of Apps (if needed, 34 total) Facebook Skype Twitter Tumblr I'd Cap That (lite) Burn the City Diner Dash Flow Free Logos Quiz Game Minecraft (lite) Slice it (Full) Subway Surfers Temple Run Temple Run 2 Unblock Me (Full) Where's My Water (Full) Wipeout Dash 4 Pics 1 Word 7 Little Words Angry Birds (Full) Bag It Bounce On (Full) Cut the Rope (Full) Doodle Jump (Full) Doodle Snake Finger Slayer Finger Piano (Full) Line Surfer Moron Test Parking Mania (Full) Rail Maze Smack That Gug[l?] Veggie Samurai 100 Floors So roughly, how much space does this take up?
http://answers.yahoo.com/question/?qid=20130224191530AA7BgY3