Good idea, will probably add locked icons soon, thank you.
thanks for comments on element and hud visuals - I find it important to get everything well-readable, so I will adjust the bars and touch up elemental art.
Terra just sort of represents plant-life or earth, though it can manifest in physical force. Terra spells clear up water blocks because [explanation in development] the water is used as fuel for the plant-matter :)
Glad you mention mana regen, I'm reluctant to have any systems which involve waiting to refill guages. I want the player to have agency over regenerating resources, but I also agree you should never get caught in a mana draught like that - it's not fair, and disincentivises spells.
I have a planned system in which your most previously channeled element is your Major, which determines a passive Aura, one of which involves higher mana regain (from melee). In the case of an aura, I will be more lenient on having a mechanic refill mana over time. I think it can add nuance to the spell slinging and combat.
Once again, this will depend on the context. The planned game will involve much more spatious rooms and functional enemy ai, which will change the dynamic of combat from a claustrophobic mess to something else, we'll see (next demo day? maybe?)
I appreciate the feedback, thanks for playing!