Great game. Very clever and original.
Next time though Dev, please place just a little more leeway in the control system. Spikes kill you when you're still 1 or 2 pixels away, and switches trigger for the entire size of their tile it appears, not just the button size.
Now, that'd be ok if Spewer actually responded promptly, but he doesn't. You made him "bounce" a little after he lands - which looks cute - but it ALSO tends to move him that extra pixel or so that will put him on to spikes or over ledges.
Either make the spikes and ledge less responsive or (preferably) make any "bouncing" of the player just a cosmetic effect - don't move the player's hitbox unless they're actually trying to move him.