Hi. I've recently started a video series taking modded characters through the arena and I've come up with some feedback and suggestions that may be useful.

I recently got a Head of the Keeper run and while drafting passed up Humbleing Bundle, but was brainstorming the cool ways I could utilize Restock and these items only to find out that the shop wasn't restock friendly anyway.

It got me thinking about ways the shop section of the arena could be improved:

Always offering a selection of 1 Red Heart/Soul Heart/Black Heart (one item with a weighted random roll on which one it will be), 1 Key, 1 Bomb, 1 Trinket, and 1 Passive Item. This would allow for more consideration on taking items that synergize well with the coin drops on the room and offer health solutions for characters that can't utilize red hearts.

Restock affecting these items would allow players who went heavy on money synergies or got lucky with A Dollar or something similar to take full advantage of their items.

Adding one or two beggars to the shop or item phase could allow players to take advantage of items dropped from things like sack of sacks, bomb bag, rune bag, etc and allow players to choose between leaving the red hearts on the ground for future use or to try to roll the demon beggar for additional items. Key beggars could be used for chest potential as well as just spawn golden or eternal chests.

The boss turrets are rather uninteresting and lead to tedious circling movements. Their function as zoning enemy can be achieved without having the fire rate nearly as high as it is so that players with low range can actually take get in there and get out without taking a shot to the face. Right now they're quite a chore to play against and they're not at all interesting compared to other bosses since they are just static entities with one attack.

Alternate turrets could also be introduced like one that spawns troll bombs, magnetic turrets, turrets that spawn normal enemies, etc.

Adding the chance of normal enemies to some of these ways or even normal enemy spawners to some waves could make them a lot more interesting. There are already some incredibly difficult waves, but some of them are comparatively very empty or just not interesting. Adding normal enemies like Vis, Knights, and Leechs could shake those waves that just aren't very powerful up.

I'm not sure how the current mod decides what enemies should be paired up together, but there could definitely be some dynamic balance added. For example, The Adversary alone isn't a particularly difficult boss, but getting three adversaries is basically assured damage. Adding on a few more bosses like Daddy Long Legs or Cage and it becomes a terible wave full of unavoidable damage.

This could be somewhat solved by having a maximum "power level" for each wave that increases by a set amount over waves. Give each boss a static power level and a "stack limit" to make sure things like 3 adversaries can't happen and then the rest is history. Waves should automatically get more and more difficult and allow for many more combinations than handcrafted waves.

I played this mode when it first released way in the early days of the API and I'm happy to see it's come this far, but it still has a ton of room to grow.

If you're interested in implementing any of these ideas and want some assistance, feel free to send me a message. I would love to help make this mod even better.

If you're not interested in these changes, please consider implementing an API for your mod with callbacks for certain actions (item pickup, arena room entered, wave start, wave end, shop item pickup, etc) so other modders can create mods for the Arena mode. Support for mods to register their custom items with Arena mode could also be added. I could help you out with that as well.

Thanks for the fun mod!