5n3k is super difficult! But the way you have it set up for infinite lives but you take a heavy score penalty makes sense. Communicating that more clearly would definitely help with player's perceptions. I finished the course though and took second (for now) 
Cool concept. I found that having a tail around moving objects to be very hard to keep control of
The biggest spots for improvements imo are
- Communicating how score works, like showing how much you got for collecting the pickup. I assume the timer was for bonus score? I also don't know what the x2 x3 etc combo means, if I'm getting 10x the score or if I picked up 10 fast.
- The borders are super punishing because they block your input for half a second. I lost a lot of lives because of this. The walls are also not at the edges of the screen so it's really hard to know how far you can go before getting bounced and input locked
Cool idea to combine snake with a scroller, and your visuals are very good!