This is a pretty neat idea! I like the idea of chess with custom pieces, sorta like Stratego. The rewind mechanic also made attacking a lot more of an option than actual chess because your piece would rewind into safety. Thanks for sharing!
There were a couple things that I would suggest. The pieces looked very similar so it was hard to tell which piece was which. It was also hard to see where the enemy went when they captured one of my pieces since they pieces would snap back immediately. I would suggest some sort of moving animation or something.
The bike mechanic was really cool too! It was neat how it wasn't an actual piece on the board and instead was on the outside. Great job!