This demo is packed with mechanics! The anims are punchy and readable. The weapons, items, and environmental damage functions will need good scaffolding and maybe longer tutorials. 

Your play style reminds me of Killer Queen and TowerFall---many small interactables, cute deadly enemies, pixel effects, plenty room for chaos and the tiny-world atmosphere.

For new players to this genre, I recommend a small arrow that pops up when they're next to walls, floors or roofs they can walk through or phase through, similar to TowerFall. 

I also recommend the tutorial introduce only 1 or two mechanics per room area. Introduce movement and pushing items in first room----attacking with weapon + attacking the environment in second room---then usable items, AOE bombs & item types in the third room etc.---you get the point.