didn't play the DD15/28 version so this all new to me. was a lot of fun and was able to complete the mission without much hassle.
movement is fast and feels nice, the railgun was very fun to use too, there's enemy variety, all in all a fun time. i was able to beat the mission in about 10minutes of playtime.
my only suggestion would be to lower the visual feedback on hitting enemies. having both a red flash and a stagger is too much, you could probably do only one of those and convey the same information, especially since the animations are very clear. personally, i'd lower or get rid of the red shader effect.
everything else is smooth, i had 0 bugs or errors.
keep up the good work