Some bugs: 

• Collecting a health potion gives you unlimited uses (probably the trigger to tell if you have one is never reset after use)
• The walking animation is jittery (look into the animation itself)
• The entire walking animation loop plays once when movement is only tapped (could be intended, but if you want to change it, look into the transition in the Animator)
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It's a fun little rougelike. I thought the lack of directional attacks (above and below) would be an issue, but it ended up playing just fine since enemies are also very horizontal. It's a bit hard to dodge fireballs, but there's enough counter play in possibly running away or charging them first. The giant ghost I've been unable to kill without taking damage however. There is enough health potion drops so it doesn't feel too unfair. The attack animation felt a bit tight (hitbox) but it wasn't too big an issue. It occasionally allowed some ghosts through that I thought should have died but it didn't happen too often.

Great job overall!