Short: collect coins, move to exit.
Extended: there is two types of levels in game: single-pass levels and double-pass levels.
1. Single pass: collect coins, move to exit. Avoid spikes, handle disappearing tiles.
2. Double pass:
a) Time your actions.
b) First pass - collect coins you can get, tap triggers (if any) for second pass.
c) Second pass - collect remaining coins, while your shadow will repeat previously recorded actions. Move to exit.