1001 Spikes allows you to skip levels. What are the consequences, if any, of skipping a level?
The only consequence for skipping a level is that you won't be able to access stage 6, fight the final boss, and obtain the good ending. Instead, you'll receive the bad ending where:
"Professor Hawkins is never seen returning from the tomb".
However, as long as you go back and successfully complete all the levels, then you can proceed onto the final battle and get the good ending.