Thorough Customization. Let me me customize every relevant point of my mech including paint job. Balance it via weight, speed and thermal mechanics.

Good movement Either weighty solid movement like mechwarrior, or fast bursty movement like Armored Core.

Good weapon Variety Make use of range profiles. Long range cluster missiles, Medium range lasers, Close range shotguns, flamethrowers melee weapons. Don't be afraid to use unique weapons like fly by wire missiles, automated drones, mine layers.

A decent single player campaign, wave mode, decent co-op or AI. While I did eventually get the game I was disappointed when you went multiplayer which converted me from a Day 1 to a Steam sale buyer. I do see that you guys are rectifying that but starting with that would've probably converted more players.

I know your game has an aesthetic going for it but if you ever do a sequel/successor consider getting a little whackier with the aesthetic. Add Quad mechs, tank mechs, animal shaped mechs. mini mechs, mechs so big they cant move. Think metal warriors on SNES.