This is a sick game and a great idea. I don't know why I've never seen an arena style platforming survival game before but it works so well! I did have some trouble seeing potions like someone already mentioned but other than that the game is sick!
An idea that may be worth thinking on is giving an incentive for the player to move around the map more. Like maybe a pickup that reduces the timer or something... The potions do a decent job of this but I found that sometimes it was just better to chill in one spot of the arena and focus on dodging things there instead of continuing to move, but moving was the whole fun bit! IDK, just a thought I had. Great work though!