You need a fluid, almost-swaying motion when you hitting chords like that, it should come from the elbow, not the wrist. + Sounds boring when all you're doing is down-stroking. Plus as Mental said. there's something out of tune there + I've noticed a lot of sloppiness with muting (which could be that 'strange noise'.
The vocalist changes key a lot. Try having a go at alternate picking too, as in Dakota, it seemed very bland.
In this situation, I'd sit down each instrumentalist, ask them toi go through the song, and then advise him on ways to improve. Go around the band until you've ironed everything on. Rehearse as a band again, then working on rhythm/timing.
Keep at it, you'll get it eventually.