A few changes and additions for pc players.
Have you thought about creating an easy to download client for Miniblox as a way to solve lots of issues people get via browser? PC players will probably or most likely get rather high performance increases (on the average PC*). (They don't know how much they needed it till they truly have it in their grasp.) E.G. Ctrl+W = closing browser when not in fullscreen.. Ctrl + Scroll up/down = GUI Scale change and a non accesable hotbar.. uncapped FPS.. Maybe less server stress? Not sure about that though. Also add 1v1's for players who like hand to hand combat. I suggest boxing (First to 100 hits, no damage is done), Sumo (first to knock the other player off), BuildUHC (A sword, axe, pickaxe, wood planks, cobblestone, 2xLava bucket, 2xWater bucket, 3 - 5 Instant Golden Apples/Golden Heads, 5 - 10 normal Golden Apples, a lightly enchanted bow, a fishing rod with unbreaking, 32 - 64 arrows), MiddleFight/Midf.. Also better audio so far away players actually sound far away instead of 1 block away. Maybe for the client, a render distance option of up to 16 or more? Move the clock/Kit Changer item from the 9th slot to the 7th or at least movable so PC players dont accidentally hit scroll wheel when left clicking (Jitter or butterfly for example) and accidentally choose a different kit midfight. On the client, please make mouse movements more responsive. When i move my mouse rather fast to attack the player behind or beside me, but the game doesnt register it. add slightly better bow physics, so bow boosting is avalible to players who know how. Maybe add an option for more experienced players to join (for example..) classic PvP for more experienced players. Maybe lessen the hit knockback's horizontal velocity? Sorry if this is a lot, but I hope it sparks a few ideas.
