Mixed resolution makes this seem weird. Maybe it's not a mixed resolution but those foreground bricks are strangely done. you also could benefit from some variation tiles. For w.e reason this reminds me of Sonic, and could provide a great resource to reference. I like the red/green (maybe its closer to yellow/greenish blue now) interplay btwn the bg and the foreground. You also gotta add some fading bricks or something to transition into that darker area. Those spikes are also in the wrong perspective, they have to be more head on, side view, like the bricks are.