However, if you'd like to think out-loud about what you might like to see, I'm sure there might be some other unofficial commentary.
Well, here goes:
-Name in credits
-Forum badges (tiered)
-Message log (pickup item) with backer's thematic message (appear on console). Subject to approval.
-Custom mech skin
-Custom bullet skin (Minigun only or favorite gun?)
-Make an item with devs: Regular, sac, secret.
-Make a weapon with devs: Main, secondary.
-Make a launcher with devs (Goldenwolf?)
-Make a drone with devs
-Make a mech with devs
-Design a regular enemy with devs
-Design a miniboss with devs
-Design a condemned challenge room with devs
-Design an early boss with Misery: 1-2 phases.
-Design a late boss with Misery: 2-3 phases.
-Playtime: Using Steam's spectator function (or equivalent), play the game while chatting with a dev (or the other way around, watch him play while bombarding him with questions :P) for 1h. (time extension addon?)
-Muse reward: Design music track with Pablo Vega.
*Balancing and tweaking up to devs. Designs have to be within game current capacities. Batteries not included.*
I know many of those are expensive and/or time-consuming ideas, but these are the things I think would make good backer rewards for the kickstarter.