Solitomb is a multi-cart game, so please make sure:
- that you have all 4 carts in the same directory
- that you're starting the game from the "solitomb.p8.png" cart
An outdated PICO-8 version on the device can also cause trouble like this. In general, Solitomb is not that great to play on portable consoles just yet, if only because it has only mouse controls, so I don't want to get your hopes up too much. It is playable if your device has mouse emulation.