Just stumbled upon the demo! Here are my thoughts:
+ Solid Gameplay and Aesthetics that put the man vs. army frantic feel of Metal Slug into the sci-fi trappings and adaptive strategy of Mega Man (as advertised) but with enough of its own flavor to feel like its own thing.
+ M16 feels like a rough and tumble little badass who is never out of options (with one possible exception, we'll come back to that) in a fight: I genuinely love how his primary weapon system and shields are tied to his energy supply but depleting it never means you're waiting for weapons to recharge to shoot again, nor does the shield just automatically drain by using it... and the bonus of the shield healing him at low health as well as deflecting projectiles is another welcome touch.
- I was a little disappointed that firing one of M16's secondary weapons halted the recharge of his primary systems: Since they can't be fired simultaneously their purpose (while still cool) the secondary weapons (shotgun and machine gun thus far?) feel a tad muted thanks to this as they don't seem to offer much appreciable gameplay enhancement.
- While I'm super glad the game is free of a life system, it is definitely quarter-munching tough even on Normal Difficulty to that point it can be just a touch grating: The enemies are just a little too unpredictable and fast to properly manage in swarms (there were definitely two points in the demo where it was a noticeable problem for me) and at least one enemy has a range and speed that require a level of timing that (I personally at least) found to be a little too much to tackle right now.
While some of that amounts to balancing polish, perhaps one of the things M16 would benefit from would be a melee strike or a shield burst to give him a little bit more breathing room for tactical retreats... even a strafing function that maintains his direction while he jumps and dashes might be useful.
Overall however I have to say that I'm excited to see what a full version of this game could look like: It shows incredible promise and even if the additions I mention weren't implemented Operation Echo could still be a blast!