Started out really good, but fell down flat when I found out I was at level 7 in a chunk cut out of a flat world filled with slimes by day and nasty mobs at night.

Need to lose the land mass...

Also missing some items, which should have been in the chest or on another island.
-Pumpkin
-Second water or ice block, for infinite water supply
-Melon

My single water source is currently powering the cobblestone generator and watering my farm at the same time

Also, you cannot place blocks on the chest, so it could do with some bedrock under it. Although, I worked out how to bypass this problem after a few deaths...

I wasn't spawning on the chest after my death, I spawned in the start room with a button that didn't work a second time around.

Recommendations...
-Lose the land mass
-Block up to level 100 to get rid of slime problem (slimes spawn below level 40)
-Bedrock under chest
-Add grass block to chest or a small second island with dirt  and grass on it, with a pumpkin, Melon and a 2nd water or ice block for an infinite water source. The small island with dirt and grass blocks, would allow me to get animals to spawn naturally
-Fix the respawn problem

Don't get me wrong about my complaints, until I encountered the endless flat land and missing items, I was really enjoying the Skyblock.

I only commented because I wouldn't mind playing it again, If you fix the easily fixed problems as it was a lot of fun...