Nice job! You made great use of available time, this game doesn't feel shallow like some jam games do
* It'd be nice if the nodes had place/walk sounds, and the water/lava had liquid properties (For more 'MTG-like' scenes) with ambient sounds.
* Make the music go as a background behind sounds added above, and add a track or two more
Things you might want to fix:
I had a hard time telling blocks apart visually, having to look at the HUD for what a node was broke the immersion.