Please note: i am not very good with art or filling blank spaces so just take note of that! Also as this is my first time doing ludam dare i have learnt what not to do during the making of the game.
Congrats on your first game jam entry! No better way to learn than a game jam. You've got a good start here. What you need is a build up towards the main objective, killing the big blob. Throw in some little blobs here and there, something to do and a small obstacle for the player. Take your ground and make some platforms in the air. Maybe a pickup here and there. These will all add depth to your game. The sky's the limit. Also make some sound effects for the blob and pickups. A good game with bad sound is okay, but an okay game with good sound is awesome!
You have a good start though, and congrats again!